Excel 2003 - PDFCreator reference missing

Hello. I have developped on Excel 2003 an application. This application made some HTML document with the data stored in Excel files and I use PDFcreator to print the HTML files to PDF files. In my computer and other computer of my office network, I have no problem. In my personal computer, no problem. But when I try my application on the customer office, I have a problem : The reference "PDFcreator" is marked "missing" on the "References" Windows.

For information, the customer user have Administrator right. We have to uninstall PDFCreator and install the version used by the application. We have install the last version. But we have the same error "Missing PDFCreator".But there is one computer in my customer office where the application works (the user have installed PDFCreator himself). So I think there are some network policies on the network custumer.

Questions : Can you help me to solve this problem? Is it possible to add manualy the PDFCreator reference in Excel ? Is the order of installation of software may be causing the problem (I always install PDFCreator before Excel?

Thanks for your help.