If you are using the Acrobat SDK to control the print functionality in Acrobat/Reader, or to write a custom print plugin, you will need to use the function: AVDocPrintPagesWithParams(avDoc, &docPrintParamsRec);
This is a limitation in the Acrobat SDK as it still uses short printer names. In the Acrobat standard printer dialog, there is no limitation as the dialog uses internal methods which have already been extended for long printer name support.
The Acrobat 9 SDK will resolve this issue and add support for long printer names.
Please refer to the following link for the declaration of the AVDocPrintPagesWithParams function (pg: 1713):
it is discussed again here: