mfxnt.sys for scanning does bluescreen

Hello,

my laserfax philips 855, supported by sagem, works a long time very well. Suddenly, when i want to scan a document via paperport, i get a bluescreen with the advice to mfxnt.sys. This happens as well, when i want to start photoshop.
whith this software i can now only work, after i had renamed mfxnt.sys, located in windows/system32/drivers. But scanning i have no chance.
Sagem-support couldn`t help me.

Lothar