>What does this error message mean? I mean, other than 'An invalid index key length has been specified. The length of a key for an .IDX index must be between 1 and 100 characters. The length of a key for a .CDX index must be between 1 and 254 characters.' VFP 3.0b help file.
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>I got this message when I tried to add an index to a table in a dbc. The index I tried to add was named 'JobName', the type was 'Regular' and the expression was 'JobName(cJob_Id)' where JobName is a procedure defined in the dbc's Stored Procedures. It returns the character name field from the Job table for the record id passed to it.
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>This table also has 8 other indexes. Six of those indexes are on secondary key fields that are 6 characters in length. One index is DELETED() and the last index contains a procedure similar to the index that I'm trying to define.
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>Am I placing too much of a burden on the .CDX file of this table?

If you really should have index on some calculated result (for Rushmore?) then it's probably that you could maintain one more field in your table and index on this field. I've never used index on function return value.