Error launching portable software on windows 7

Hello all, I am new to this so I am sorry if this sounds stupid
I have been using portable applications for a while now and recently upgraded to windows 7 but every time I try to launch an application it gives an error message

'Main program has stopped working,
windows is searching for a solution'
and soon after the application shuts down, some applications have a little pop app on the side saying something about thinapp suit packer

all these software ran well in xp, but I can't even run firefox or skype any more..
can any one please tell me what's going on with these error messages

thanks