microsoft+excel+training - Linked workbook - "formula too long"

I'm using Excel 2002 (10.4524.4219)SP-2 and have a number of workbooks with multiple worksheets, all in a similar generic format. All behave perfectly when linked to other workbooks apart from one.

I need to change the source to this spreadsheet and am using Edt / edit links / change source but when I browse to the new file and double click I get the error message "formula is too long".

This is a fatal error, Excel locks, so have to use cntrl_alt_del and then end task from task manager.

Any hints?

many thanks, Cameron