Cannot Save from Excel 2003 to networked location.

I am working witn an end user who has Office 2003.
Everytime she tries to use the “save as” option, chooses a networked location to save the file, she gets the following error “ cannot be accessed. The file may be read-only, or you may be trying to access a read-only location. Or, the server the document is stored on may not be responding.”
The current file she works on is not read only.
She’s able to save the file to her local machine, then copies and pastes it successfully to the desired networked location. But, of course, as all end users demand, she wants to be able to use the “Save As” option right from Excel 2003.
I have not been able to find any applicable solutions to this issue for Excel 2003. Anyone have any ideas/suggestions?