Couple of random thoughts here. Zip the EXE and try copying it to the SAME place you tried copying the EXE. What is the result?

Log on as an admin to that workstation and retry? Same result?

Log on as an admin w/ no logon script specified and retry. Same result?

Open up a command prompt and type echo %logonserver% to find out which domain controller authenticated your session. That will tell you where it is looking for logon script files. It could be that the machine isn't finished with the logon script yet and you're trying to copy a file in use.

HTH,
Tim