Another application in use

iTunes error 9006 may appear when attempting to download, restore, or update an iPhone or iPad. Typically you'll see an iTunes error message that states something like "There was a problem downloading software for the iPhone. An unknown error occurred (9006)." Try the following tips to resolve error 9006 in iTunes if you encounter the error problem when updating iOS system software.

1. Insure that you have an active network connection and are connected to the internet
2. Quit out of iTunes
3. Update iTunes and also install any available software updates to Mac OS (or Windows, if applicable)
4. Reboot the computer (Mac or PC)

If above methods fail to help you out on the error 9006, get more solutions here: fix iTunes Error 9006 with 6 useful ways. Hope it be helpful for you.

5 methods for you:
1. Fix iTunes Error 29 by Factory Reset (Data Loss)
Factory resetting could solve most of the iTunes error 29 cases, however, it would erase all the contents on your iOS device. You’d better backup your device in advance.
Here is how to factory reset an iOS device.
Go to Settings > General > Reset, click on Erase All Content and Settings.
2. Fix iTunes Error 29 by Keeping Anti-Virus/Anti-Malware Application Up to Date (Complicated)
Anti-virus and anti-malware applications could protect our data, however, as time goes by, those applications could become outdated and cause iTunes error 29.
Updating those applications is easy. All you need to do is to go to Apple Store and do reinstallation. However, that could be troublesome for users who own multiple anti-virus/anti-malware applications.
3. Fix iTunes Error 29 by Updating iTunes on Computer (Time Consuming)
Besides outdated anti-virus and anti-malware applications, outdated iTunes on your computer could also cause iTunes error 29.
Here is how to update the Apple operating system.
On Mac:
Open iTunes, from the menu bar at the top of your computer screen, choose iTunes > Check for Updates, then just follow the instructions, you are able to have the latest version of iTunes.
On PC:
Open iTunes, from the menu bar at the top of the iTunes window, choose Help > Check for Updates, then follow the prompts, you can download the latest version of iTunes.
Please note that using iTunes to restore iOS system could also cause data loss.
4. Fix iTunes Error 29 by Reinstalling the Battery (Risky)
Battery issues may also cause iTunes error 29. Below are ways to reinstall battery, we recommend you try this method under the supervision of a specialist.
What you will need are two screwdrivers, a suction cup and a plastic pull tool.
Step 1. Hold the Power button to power off your iOS device, then remove the two screws on the left and right side of the charging port.
Step 2. Use the suction cup to lift the screen a little bit, remove the screws that lock the battery connector to the battery retaining bracket.
Step 3. Use a plastic pull tool to lift the connector, wait a few seconds, now put everything back.
5. Fix iTunes Error 29 without Data Loss (Easy & Fast)
As mentioned above, both software and hardware could cause iTunes error 29. If you are encountering iTunes error 29 caused by software, PhoneRescue – iOS data recovery could help you fix it with great ease and you don't even have to try other methods.
These methods are listed in an article from imobie.com; hope one of them works for you.

No, but if you are not show you can locate the musics you purchased from Itunes, remember it is not stored on Itunes application instead it create it own folder in your my computer under music.
copy all the items there and create new folder for it before uninstalling Itunes from your computer.
I hope this works for you.

Launch Internet Explorer
Click the Tools menu
Select Internet Options
Click the Connections tab
Click the LAN Settings button
Make sure that that "Use a proxy server for your LAN" checkbox is unchecked
Click OK till you are out of everything, and then close Internet Explorer
Try again in iTunes to load the store

if this dose not work

Then it is your security that is blocking you

try this

Sometimes this error can be caused by software on your computer that slows down the network connection. This error can also appear if you are downloading multiple items. I'd like to provide some steps that should help you successfully download your purchases.

It often helps to pause the download and then download items one at a time. These steps will walk you through doing this:

1) Open iTunes.

2) From the Store menu at the top, choose Check for Available Downloads. If you're unable to upgrade and are using iTunes 7, the option will say Check for Purchases.

3) Enter your account name and password, then click Check. Your purchases should begin downloading.

4) Under the STORE section on the left, click Downloads.

5) Click the Pause All button in the lower-right corner. This will temporarily pause all of your downloads.

6) To resume only one of the downloads, click the refresh button that appears to the right of one of the paused downloads.

Certain types of software can affect the way a computer sends and receives information from the Internet. Here are a few examples of these types of software:

• Firewalls
• Web accelerators
• Ad filters
• Virus protection software

If you have any of this kind of software installed on your computer, you will need to configure each of the applications to allow your internet connection to access iTunes freely. For instructions, please refer to the documentation that came with that software, or contact the software's manufacturer. You'll need to configure the software to allow these domains to send and receive data from the Internet freely:

itunes.apple.com
ax.itunes.apple.com

For assistance in configuring your firewall or accelerator software, you may need to contact the manufacturer or your Internet service provider (ISP). When contacting their support representatives, it may be useful to have the following information:

"Well Known" TCP and UDP Ports Used By Apple Software Products
http://support.apple.com/kb/TS1629

The following article helps Windows users pinpoint software conflicts that could cause the error:
Using MSCONFIG to troubleshoot conflicts in Windows XP
http://support.apple.com/kb/HT1275

Using MSCONFIG to troubleshoot conflicts in Windows Vista
http://support.apple.com/kb/HT2292

Once you have managed to allow access to iTunes through other software, please follow these instructions:

1) Sign out of the iTunes Store.

2) Quit the iTunes application.

3) Restart your computer.

4) Open iTunes.

5) Select Check for Available Downloads from the Store menu at the top of iTunes, (if you're unable to upgrade and are using iTunes 7, you'll choose Check for Purchases).

If you can't find this option, you can also click this link to do the same thing:

https://phobos.apple.com/WebObjects/MZFinance.woa/wa/checkForPurchases

6) Enter your account name and password, then click Check. The missing item should begin downloading and appear in your Purchased playlist.

Please note that the iTunes Store cannot investigate every user's connection issue. Apple Discussions are another source of information about iTunes, where everyone from new users to professionals can interact and share their knowledge and experiences. You may find another user with the same operating system or ISP that may be able to help resolve this issue. You can find the iTunes discussions group at:

http://discussions.info.apple.com/itunes

If you are using a dial-up connection, you might consider downloading your purchases over a broadband connection, if you have access to one.

The following alerts may appear when trying to download purchased content from the iTunes Store:
"There was an error downloading your purchased music. An unknown error occurred (-50)." This can happen when the connection timeout occurs while downloading purchased content from the iTunes Store. Certain types of software may also affect the way a computer sends and receives information from the internet. Here are a few examples of these types of software:

• Firewalls
• Web Accelerators
• Ad Filters
• Virus Protection Software

try to disable them for a while when you download something from iTunes.

The software should have a list of the Apple products that you own that can be updated by the Apple Software Update. You need to select the product from the list, and then it will give you the option to Install.

If, for some reason, the software is not working correctly, you can always reinstall iTunes

http://www.apple.com/itunes/download/