You are right! Actually there is a small networked environment, Server using NT4.0 SP6 and is the host of the application and database, Workstation using Win98 SE. Things happened from any of workstations, never found in server, but i think it is just because no one use the server to input data.
The version of VFP is 6.0 and the application is complied to EXE.
I thought this may be a hardware or network problem before, but after replacement of all NIC and connections and reinstallation of NT server, the problem still there, so i think the possibility of hardware or network fault is very low.
BTW, are there any ways to attach files in UT? I think an actuall look to this table better than just describe in thousands of words.