Lookup with Picker Column becomes empty During Check-In of a File Using MS Office 2003


I created a required column using the lookup with picker in a document library.
Here are the steps to recreate the Issue:
  1. Check out an existing MS Office document in the document library (an Excel or Word document)
  2. Edit the document in MS Office 2003
  3. Save the document
  4. Click on the Check In option in the MS Office 2003 after saving
    An error will be encountered that cannot check in the document. When I investigated the properties of the modified document, the value of the Lookup with Picker column is empty. Since it is a required column, Sharepoint is not accepting to check in the document.
    I'm not experiencing the issue when using MS Office 2007. The issue is mostly encountered using MS Excel 2003.
    Thank in advance for the help!