I/O device error

My environment has 3 users with Toshiba Satellite CDS4070 laptops. These, I believe, are unique Canadian models. I have rebuilt these units with W2K Pro, all fully updated to SP3, BIOS, etc. Now, whenever the users try copying larger files to floppy, they get an error message saying that the file cannot be copied, that there is an I/O device error copying *filename* but with no error #s. Problem starts when file sizes are generally >300KB. All file copies successful at command prompt (i.e., from w/i W2K). Been on MS’ KB and Toshiba’s AskIris; also spoke to Toshiba techs. No known issues or solutions. They worked fine in W9x as well as the last user still using W98SE. Last resort – you! Thanx much for your help, Stephen