There currently is a limit in 9.4 beta on the number of merge shape files. I currently need to run 4 separate merge querries to get 1 shape file. I could do this in one step with previous versions. I am trying to merge 50 line shape files to get one shape. I need to split the 50 into 3 separate merges then merge the 3 merged shape files into 1. The program locks up if I try it all at once. Also, the process of the merge is extremely slow when compared to previous versions of ArcView. That is why I have 3.3 also loaded to run these merges.