Reproduced on Windows XP, Service Pack 2. The issue happend after updating Skype from version 6.6.0.106 to 6.10.
Solution: no need to install Service Pack 3, just uninstall version 6.10, install 6.6.0.106 and disable automatic update.
Link: http://download.skype.com/msi/SkypeSetup_6.6.0.106
Tools -> Options -> Advanced -> Automatic updates ->Turn off automatic updates
Probably installing Service Pack 3 also can fix the problem, not tested, but described solution will fix the issue 100%.
Original information was found here: http://community.skype.com/t5/Windows-desktop-client/Skype-Fatal-Error-KERNEL32-dll/td-p/1916819/page/2
6601 no longer available from Skype