Error 91(Object variable or With block variable not set)

I installed PDFCREATOR on my terminal server, when I launch PDFCREATOR the program doesn't work, the PDFCREATOR process goes "not responding".

So I launch the command "pdfcreator.exe  /CheckInstance" and this error appears :

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PDFCreator - www.pdfforge.org

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Errorprotocol

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PDFCreator  V1.1.0 - Error message

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ERROR DESCRIPTION:

          Error-Nr:   91 (Variabile oggetto o variabile del blocco With non impostata)

          Modul:       modGlobal1

          Procedure:              GetCheckProgramInstancesStr

          Line:            50070

          Date/Time:              02-09-2011 / 18:30:32

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CALLSTACK:

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SYSTEMINFO:

 Windows 2003 5.2 Build 3790 (Service Pack 1)

  [TerminalServer Win2003Server IsWinXPPlus]

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Does anyone know what is causing this please?