Thanks Haudy, it works like magic.. ;O)

I was a bit puzzled when I used HTTrack v3.20 RC3 & then 
the latest v3.21 to have it lock up in my Win XP; & now 
that I have reversed those two rules like so:

-*domain-a.com*
+*domain-a.com/filename_a*

v3.21 doesn't lock up anymore (didn't test with RC3 
however). This lock up would not happen regardless of the 
order of these scan rules in v3.04 (didn't test any other 
old version) so it seems it is a bug introduced in one of 
the later versions.

This should definitely be made more clear, or ideally, have 
a bit of intelligence, so HTTrack downloads "filename_a" 
regardless of the order in which it is placed. This can be 
assumed when all files with "filename_a" are on "domain-
a.com" -- so therefore, the intent must have been to 
download this.

If it cannot be assumed, a highlighted "warning" message 
should be easily visible indicating the discrepency of the 
rules while HTTrack continues to download, allowing the 
user to click the message to abort or change to the next 
logical mode (as deduced by HTTrack &/or allowing the user 
to choose from available options).

I know this is all overhead to the code, but in the future, 
simple things like this with intelligence can make the big 
difference..

It is free, one could argue, but that doesn't negate the 
truth that it probably would be better. Everything, of 
course, is a trade off. The question is: Is it worth it?
I would say, "yes, it is."

chris =:)