ok updated to netframework3.5 and bingo back working. but i dont understand why it stopped

hi all, come to use fecuscan for first time in ages and it just crashes. if tried reinstalling latest version but still the same problem in fact the software wont unistall from its own uninstall option just crashes again. this is what it says Error signatute eventtype :clr20r3 P1:multiecuscan2.exe P...