Hi Matt and Dianne, Sorry for the delay in my response. We are using Fedora 7 with 4 GB RAM (but I've also tried it on a Mac OS X 10.5 with 16 GB RAM). I've used both FSL 4.1.4 and 4.1.5. Both have given me the same error... It begins to preprocess, and queue the data. However, within 5 -10 minutes it prepares the postprocessing stages, and finishes up. When I check the folder, there are no fiber files, or transform files. Any ideas on how to troubleshoot? Thanks, Massih