I have found that alter table command
causes error:

File c:\temp\0502743.tmp does not exist

My program runs on NT 4.0 server and VFP 5 build 415 runtime.
c:\temp is NT temporary files catalog. Workstations can use dbf files in server normally using same common exe file located in server.
I can create and edit files in this temporary directory.
Program works about year normally. Suddenly it starts to produce this error. This error occurs always when I try to open form. Other commands which create files in temporary directory work OK.
Why?

Code causing error is:

select myTable
local lStru
dime lstru[1]
afields( lStru )
crs = 'rid_'
create cursor (crs) from array lStru
* Next line causes error
* file c:\temp\0502743.tmp does not exist. Why ?
alter table (crs) add column myColumn L