Hi Bushy,
I have had a similar problem recently, I had hyperlinks that were dynamically updated from an adjacent cell to take me to various places either on other workbooks or web URL's.
I found that if I tested the hyperlink on the first cell BEFORE i had autofilled it took me to the same URL as the first hyperlink everytime. My solution was to clear my IE cache and close the workbook (after deleting my hyperlink formula). Re-open my spreadsheet and re-do the formula this time autofilling before testing my hyperlink. It then worked a charm.

Let me know if this works!
Thanks DB2