Very unusual print problem

I have Vista Ultimate. I have a WIN 2003 Server that is a print server.
Attached to the print server I have a Samsung ML-1450 Laser Printer and a
Canon i950 ink jet. I was able to configure the 2 printers as network
printers in Vista, no problem. The test pages print fine. All applications
print to the Canon. Here's the unusual part, only some applications print to
the Samsung correctly. Word, Excel and Outlook all print to the Samsung fine.
Other applications, IE 7 and Adobe Acrobat PDFs, do not print.

I don't get an error in Windows. I just get a single sheet from the printer
with the following printed on it:

PCL6 ERROR - uL_src_Len--

POSITION : 0x11aff (72447)

SYSTEM : GP/xl_pattern

LINE : 900

VERSION : PCL6 3.06 03-05-2002

Any ideas?

Thanks in advance.