Can someone explain what this error means? User gets error:

SRVREER. Database Open Failure: I/O error for file "D:\path\file.ib"
Error while trying to read from file. The process cannot access the
file because anohter process has locked a portion of the file.

By the time I remotely connect, the program runs okay. So I'm guessing
another application is locking my file.ib and has unlocked it by the
time I connect. What types of programs should I look for?

Thanks,
Dan