Error 70 Permission Denied

Once in a blue moon I get this error message and the pdf is generated but empty/blank. 99.9% of the time it works just fine. What can cause this?

 

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PDFCreator - www.pdfforge.org
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Errorprotocol
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PDFCreator 0.9.7 - Error message
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ERROR DESCRIPTION:
          Error-Nr: 70 (Permission denied)
          Modul: modPDF
          Procedure: GetPSHeader
          Line:      50130
          Date/Time: 08-26-2009 / 06:27:02
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CALLSTACK:
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SYSTEMINFO:
 Windows 2003 5.2 Build 3790 (Service Pack 2)
  [TerminalServer Win2003Server IsWinXPPlus]
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Same here, only with 0.9.9.

Windows Server 2003 R2 SP2 (Terminal Server)