Except the comments (REM), my config.nt has the following lines:

dos=high, umb
device=%SystemRoot%\system32\himem.sys
files=40

I´ll try to add the one that you suggest (with the correct path) and see if it works:

device=x:\short_path_to_avast4\aswmonds.sys

Thanks for your help, Jindrich Kubec