Can't install driver on OS 10.6 (snow leopard) - it says "install failed" - is there an updated driver? What can I do?

You can buy in an Apple store (physical or online)
Mac OS 10 6 Snow Leopard

Firstly you will need to buy a copy of 10.6. This is available from Apple (see link below) or you could get a copy from eBay.
Mac OS 10 6 Snow Leopard

The following article will tell you what to do next:
An Easy Guide to Installing Basic Upgrades in OS Snow Leopard 10 6

Sounds like a driver issue. look to see if there is a new driver for your OS. then get back to me i can help

Seems like it should work with your OS. For drivers/information, go here:

https://www.usa.canon.com/internet/portal/us/home/support/details/scanners/support-scanners-canoscan-series/canoscan-5000f#a72cde65-eaa8-479e-94a4-0e78ce832ebb_tab

Apple recommends that if you wish to go from 10.4 to 10.6 then you should purchase the 10.6 Box Set.

System Requirements to run Snow Leopard:

• Mac computer with an Intel processor
• 1GB of memory
• 5GB of available disk space
• DVD drive for installation

Snow Leopard Installation Instructions:

1. Just insert the DVD in the optical drive.
2. Restart your Mac while holding down the C key.
3. You will be guided through the installation procedure and be prompted at one point to choose which install option you want.
4. Once the Snow Leopard install is completed the Mac will restart itself.
5. You will probably be asked to register with Apple upon restart.
6. Enjoy Snow Leopard on your Mac!

Q: Can I upgrade directly from Mac OS X 10.4 (Tiger)?

A: Yes. Apple recommends purchasing the Mac Boxed Set for this purpose, which will also update iLife (it is unknown at the time of this writing whether older versions of iLife work with Snow Leopard) and iWork. Also note that while it has been said that the $29 upgrade will work with 10.4, it is not officially supported and may be in violation of the licensing terms.

Q: What happened to the different install options? Can't I do an Archive & Install?

A: Apple has revamped the familiar installation options for Mac OS X. You now have two choices, either a straight upgrade or a clean install. Supposedly if you choose to do a straight upgrade, what actually goes on behind the scenes is what was traditionally known as an Archive & Install.

Q: Is there anything I can do to better prepare myself for the upgrade?

A: Yes. It is advisable to run a Verify/Repair Permissions and Verify/Repair Disk in Disk Utility. You may also want to run the maintenance tasks in Onyx. And finally, it would be wise to get your applications up to date using a program like AppFresh.

I’m happy to help further over the phone at https://www.6ya.com/expert/jeremy_69f3cc28d95bf514

This is the best solution for that problem and works perfectly...
http://blog.ragnarson.com/2010/01/mac-and-hp-laserjet-1018.html

Snow Leopard has a bunch of drivers built in to control various printers.  If it doesn't recognize the printer, then you will have to go on Agfa's web site to see if they have a printer driver compatible with Snow Leopard.  Keep in mind that Snow Leopard is a new OS and that printer manufacturers will take some time to update their programs and drivers to run on it.  If you don't find a driver then, you got to use a different printer or downgrade your OS to one that will run the printer.

If you updated from Leopard to Snow Leopard you should note that safari for Snow Leopard is different from that for Leopard. Do a clean instal of Snow Leopard and that should sort the problem out. Hope this helps

You can find useful information on site? http://www.epson.com/cgi-bin/Store/support/SupportSnowLeopard.jsp Mac OS X Snow Leopard Support Contact Support Welcome to Mac OS X Snow Leopard v10.6 support for Epson products. Here you can find out how to get drivers and other Epson software for your Epson product that work with Mac OS X Snow Leopard v10.6.
Check your Epson product CD to see if it already contains Macintosh OS X 10.6 drivers. If the CD indicates support for Macintosh OS X 10.6, follow the instructions that came with your Epson product to install your drivers and other software.
If your Epson CD does not indicate support for OS X 10.6, DO NOT INSERT YOUR EPSON PRODUCT SOFTWARE CD IN YOUR SNOW LEOPARD COMPUTER. Follow the step-by-step instructions below to obtain the latest software and utilities for your Epson product as they may be needed for this new operating system.
Good Luck.

Some manufacturers have not caught up and updated their drivers for snow leopard yet.  You gots ta be patient and wait a couple months or call the manufacturer and ask for a comparable driver that will run off snow leopard. Go back to the previous OS if that was working your printer.  Don't fix it if it ain't broke.