[MiKTeX] mpm.exe does not work

[<ces...@eu...>]

Hi to all members of this list:

I've recently upgraded from MiKTeX 2 UP 1 to MiKTeX 2.2, and installed =
the "Small" package distribution on three PCs with the same operating =
system, NT 4 SP 6. On two of them things work properly. On the third, =
the only thing that is not working is the Package Manager: When trying =
to install a new package, *the system* reports the error that the file =
miktek-zzdb1.cab does not exists or is being used by another =
application. In a previous installation of the same package on the same =
computer, the antivirus VShield had reported that this file, =
miktek-zzdb1.cab, contained a virus, which is obviously false. =
Nevertheless, turning off the antivirus does not resolve the problem.

My apologies if this topic has been already considered on this list; and =
thanks in advance for the replies, if any.

C=E9sar