ok i know that dreaded richedit line insertion error, let me see if i can find where its occuring and have a version for you to test before this weekend.
email me at email@example.com so we can correspond about it.
ps. my memory of the nature of the bug is that it is caused by some semi-faulty dll on the system, but i have an easy workaround if i can find the place in the program triggering it.
ps. since this is a program from the program itself, it seems like its installing fine, just having this error at startup.