See
here for more info on setsecurity. If you haven't ever used similar programs, whenever you are installing apps, you will see a message "The program is from an unnknown publisher. You should install it only if you trust its publisher......" If setsecurity is used, such trusting step is bypassed.
I remember I have had exactly the same problem before. I recalled that I disabled the setsecurity and it worked again.
A side issue, do you install mortscript on storage card or main memory? Apps installed in storage cards may not be available at the very early stage of startup, which may also cause the message you posted. Try install it in main memory if not already.