To create the dump, download and run http://public.avast.com/~vlk/hangrep.exe . In the list of processes select avastss.scr and use the Save button. This generates a file which you can either send to his email address vlk (at) avast.com (if it’s smaller than e.g. 1 MB, ZIPed), or upload to ftp://ftp.avast.com/incoming
The command-line version http://public.avast.com/~vlk/userdump.exe . The syntax is userdump.exe avastss.scr c:\avastss.dmp
(producing dump file in the root of C:\ drive)
Also, check the folder \data\log
Are there any files called unpXXXX there (where XXXX is a random number)?
If so, send them to vlk (at) avast.com
They may contain more information about the problem (maybe a link to this thread).