Run google talk with the following switch: /nomutex If you installed google talk to the default location, you can easily create a shortcut to this setting.
1. Right-click on the desktop
2. Select New
3. Select Shortcut 4.
Paste this into the text box: “c:program filesgooglegoogle talkgoogletalk.exe” /nomutex
5. Click Next6. Name it whatever: Google Talk Multiple, etc.
7. Click OK until you are done
If it doesnt work, try this
Changeremove .exe extension