Can't tell from what you've described why it would "hang" while creating PDF's, but...
"The database she accesses is on a network share. Some times she opens it directly from the share, other times somebody else on the network is sharing the database."
This is a very dangerous way to share a filemaker database. It should first be opened directly by the host computer (The computer to which the hard drive storing the file is directly connected) and all users should then use Open Remote to find and connect to the hosted database.
In regards to PDF's, it will help to more fully describe what you are doing.
Are you choosing Print from the file menu and then using a PDF utility to generate the PDF or are you using Save/Send records as PDF?
Does a PDF file get created before filemaker hangs?
Is this part of a script?
What settings are you selecting when creating the PDF?
Is it always the same layout or same record?
She selects File->Print and chooses an Adobe PDF printer from the list. I created a new printer that forces all of the PDFs that get created into her My Documents folder. Previously, the setting was to prompt for a location.
A box pops up after you click the print button which is basically the print job spooling, which is where it all hangs up. No output is created, but the job can be seen as being spooled in the PDF printer. It never progresses beyond this point.
Other times, it will create a PDF file with no problem.
It is not always the same record, but I guess it is the same layout. They are invoices that she is trying to make PDF.
See if you get the same issue when you use Save/Send Records as | PDF...