Continuous restart after Avast 4 Pro update

Avast Free Antivirus / Premium Security
1

After program update I selected restart. Now computer continuously restarts. Selected “Do not restart on system failure”. Message:
Aavmker4.sys
PAGE_FAULT_IN_NONPAGED_AREA

Technical information:
***STOP: 0x00000050 (0xEOAD0000,0x00000000)
0xF9900223D, 0x00000000)
***aAVMKER4.SYS - Address f990223d BASE AT F99000000, DATESTAMP 447d59f7

This is an HP dc5100 PC, Windows XP Pro SP2. Any suggestions on how to fix?

2

There should be a minidump file corresponding to the crash (in Windows\Minidump folder).
Can you please send it to vlk@asw.cz for inspection?
Thanks.