Battery will not charge and red symbol appears

Turned off the tablet, unplugged the charger and kept the tablet off for about 30 minute to one hour, plugged in back the charger, then turn on the tablet. After that I you might see the tablet started charging. Good Luck.

Constant BATTERY on screen indicates near DEAD battery.

CHANGE UR BATTERY. UR BATTERY IS DAMAGED

Turn the iPod Touch off and then back on again. Here's how: Press and hold the Sleep/Wake button on top of iPhone for a few seconds until a red slider appears, and then slide the slider. Then press and hold the Sleep/Wake button until the Apple logo appears.
If this doesn't help, try to reset the iPod touch while it is connected to power. To reset, press and hold the Sleep/Wake button and the Home button at the same time for at least ten seconds, until either the Apple logo or battery symbol appears. If the battery symbol appears, continue to charge the device until it is fully charged.

your battery seems to have a damaged cell, replace the battery and it should run fine

First try to replace the battery, a drained or low voltage battery won't charge up.

For infos on how to fix the Sony Ericsson Xperia X1 Not charging:
http://mobilephonerepairguides.blogspot.com/2011/01/sony-ericsson-xperia-x1-not-charging.html

bad battery, no battery conection, no battery found

thats a symbol of phone charging,just live it for a while about 30min or more.

This symbol means that the backup battery needs to be changed. The backup battery is a button-type battery, CR1616. It is located under the main battery behind a small square panel. Instructions for changing it are in the manual -- look under "backup battery" in the index.