Error converting RTF to PDF

Hi,

I don't know why or how, but some of my users reported failed RTF to PDF conversion, but when I tried to execute it by myself, it worked fine. The RTF contains a BMP (on the header) of about 750Kb (ok, I know, it's suicide, but I already asked the user to replace it by external file). When they converted the file, the result was something like this (PDF code):

/CreationDate(D:20080903120214)/ModDate(D:20080903120214)/Producer(wPDF3 by WPCubed GmbH)>> endobj3 0 obj <</Length 6265 >>streamq q 0.120000 0 0 0.120000 0 792.000000 cm BT 1 0 0 1 0 0 Tm/F1 100.000 Tf 0 Ts  0 g -0.029 Tc 783 -389 Td(280000000

But when I converted the RTF file it becomes:

/CreationDate(D:20080905143313)
/ModDate(D:20080905143313)
/Producer(wPDF3 by WPCubed GmbH)
>> 
endobj
2 0 obj 
<<
/Type/XObject
/Subtype/Image
/Name/wpt1
/Width 776
/Height 173
/BitsPerComponent 8
/ColorSpace/DeviceRGB
/Length 66941
/Filter [/FlateDecode] >>
stream
XXXXXX (it started the binary code)

Is there anything that could raise this problem. OS Version, DLL version, Installed ServicePack, or something like this?

Thanks in advance

Alessandro