Error 207 - new column branded invalid

Hi all

This one has been driving me steadily mad for most of the afternoon.

I'm working in SQL2000 sp4. I've built a simple database to take snapshots from three ERPSs that contain related data and then analyse them to look for non-conforming records (items that are flagged differently between two systems, cost conversion errors, etc). The DTS packages all work fine, and suck the records out of the main systems without a problem.

For info, the DTS packages all work in the same way:

• Purge a holding table
• Connect to the source ERPS
• Populate the holding table via a SELECT statement
• Invoke a stored proc to make the required changes in the main table

Similarly, the stored procs all work in the same way:

• Add records from the holding table to the main table that aren't already there
• Update any records common to both:
  • If there's a record date field, have been updated in the holding table more recently
  • Otherwise, match on key fields and differ on detail fields
• Delete records from the main table that aren't in the holding table

The trouble started when I modified two of the tables to include the data that the record was last amended in the source ERPS. When I tried to incorporate this new column into the relevant stored proc, performing a syntax check resulted in error 207 - invalid column name.

I did some checking, and found out that stored procs tend to rely on what the table looked like when the proc was created, rather than what it now looks like. Accordingly, I tried creating a new proc. I got the same result. What have I missed?