Hi,
A couple of suggestions:
1. Make sure they are using the IQ Express card in class 2.1 mode by setting Class1, Class2 and Class20 to 0 either thru the API or in the faxman4.ini file. That will leave only Class 2.1 enabled and after restarting the server it will use class 2.1 whcih includes faster faxing and error correcting mode.
2. Some fax viewers arent very robust and may show an all white or all black fax when viewing files with line noise. Use the Faxman fax viewer and see if the file is still all white.
Also please start a new thread on the forums when posting a new issue so we can keep individual threads seperate to avoid confusion.