We have discussed on previous occasions possible problems with having an OSL file installed in your Extensions folder when running Mac OS 8 (technically, OSL is not needed as the software is built into the System). One specific problem attributable to this OSL glitch is Type -41 errors in the Finder immediately upon startup and/or shutdown. Based on recent items in the Apple Discussion Boards, this is currently under investigation by Apple.
I can personally attest to this problem, as it happened to me on two separate occasions. And as had been suggested by others, I not only had to disable the OSL file to fix things, but actually had to delete it from my hard drive.