Please qualify what "does not work" means...it doesn't allow you to try, you get an error message, it returns bad results?
Also, what version of Crystal?
An inherent problem with Excel is that it retypes data based on the value in the first row, so a common fix is to insert a dummy row which fully qualifies the data type, and then suppress that row in the report.
So if you have a column called Customer, and the first row is:
123
Excel decides that this is a numeric column, so place:
XXX
in the first row, and Excel will then understand the data type.
Hope this helps, otherwise post some specifics.
-k