Merging dates from Excel into a mail merge document

I'm using Excel 2003 as my data source and Word 2003 as my main document in a mail merge I've done many times before. This year, however, I can't seem to get cells with text to merge properly. OK is merged as 12:00:00 AM

The only thing I can think of is to delete anything in a cell that contains text. It's not the ideal situation, but it will do for now.

What can I do, if anything to get it to merge properly?