I have encountered this problem before and have only a sketchy idea about its causes/resolution.
I use the Replace(string, string, string, param, param, param) funtion as part of a calculated expression in a control source of a text box in an MS Access 2000 report.
It works just fine on 8 out of 9 workstations.
On one workstation, however, it acts as if Replace is not a valid function name - prompting for a value as if "Replace" was an unknown field or parameter when the report is opened.
My on-site technical contact ( I work remotely from the deployment site ) resolved this issue on another machine seemingly by installing updated VB 6 dlls. However, he assures me that he has done the same and that all references (in Access VBA code design) on both a working machine and the non-working one are the same, all patches and updates have been applied.
The machines on site are Win 98. (My development and test machines are Win XP Pro and Win 2000 Pro).
I tried with and without $ sign - "Replace(...)" and "Replace$(...)"
I also tried adding in the 3 final, optional parameters - Replace(string, string, string, 1, -1, 1)