Dear Manfred,
I installed Wufi 5.1 on my notePC and everything was finished normally.
However if I invoke wufi 5.1, an alert window of "Incompatible Version of Database. Required is Version 24.50!" will be popped up just after the Logo window and I should choose to quit the program.
On the otherhand, I can invoke Wufi 4.2 normally on the same notePC.
Of course I tried to remove both wufi 4.2 and 5.1 and install them again.
It can not fix the problem.
I was installed the trial version of master wufi on the notePC when I participate the wufi seminar in IBP on Dec 2009.
System: Vista 32bit and Intel C2D
Thank you in advance for your prompt reply.