Problem opening files with spaces in filename

I'm wondering if anyone else has ever encountered this problem. Whenever I double click on an Excel file that has spaces in the filename, I get a series of errors telling me that the filename up to the space does not exist. For example, if the the file is called C:\documents\budget proposal 1.xls, I will get a series of errors that state "'C:\documents\budget.xls' could not be found. Check the spelling of the file name, and verify that the file location is correct". When I click "OK", I get another error box that states "proposal.xls" could not be found. . . " The filename is truncated at every space in the filename. Once I get past these error messages, the workbook loads fine. I don't encounter this problem when I load the file from the file dropdown, however, this is being used as part of an automated document viewing system which process the files using the actions associated with the file extension. I'm using Excel 2000 with SR-1. Any suggestions? Thanks.