Thank you so much for your answer!
Step by step ...
Did you upgrade to Avast v.6 or do a clean install?
Both!
First I upgraded my Avast 5.1.889 (english version) to Avast 6.
When I received this error, more and more times, I uninstalled Spyware Terminator (using Revo Uninstaller) and clean all my system, keeping mine Avast 6.
Then I installed again ST, but always the same problem.
So, I cleaned once again all my O.S. by Spyware Terminator, installed ST (off-line) and update (always off-line) the ST dbase. In this situation, I mean "off-line", I haven't had no problems!
In fact, "off-line" the frame I just said befor never appear (because ST needs to be connected to show this banners).
This thesis, I suppose, is supported by the fact that I simulated just 10 minutes ago all the situation in an "isolated" (not connected to internet) virtual machine (WinXP Pro 32 bit, but not updated). I haven't had no problems!
More ...
I restored all my O.S. from an Acronis backup image (a snapshot about of January).
Then, I re-installed all my software (in particular: ST and Avast
5, not 6!).
I installed ST, updated its dbase (connecting to internet), and keeping my "old" Avast 5.
No problems.
So, I upgraded to Avast 6 (using the updating procedure in Avast 5) and here is this damned problem!
In this way, I understood (I think!
) that there is something between Avast 6 and Spyware Terminator.
And so on ...
I uninstalled Avast 6 (by Revo Uninstaller, reboot, etc. etc.) and downloaded (from Avast official site) the new cleaner of Avast to remove all (potentially) debris (reboot, etc. etc.), too.
Then installed Avast 6.0.1000 (this time the italian version). The clean was so deep (I suppose) that I had to register once again!
Anyway, I received the same error.
Since Spyware Term (ST) is a security software, did you add it to Avast's exclusions and also add Avast to ST exclusions?
I'll do this attempt and I'll be back as soon as possible.
I hope I was enough able to explain the situation ...
Thank you so much!