I have the same problem here, only that it's related to Acrobat 9 (Windows), not the printer.
I have an Indesign (CS6) document, exported to PDF with a drawing that has horizontal dashed lines. On screen and in the Acrobat print preview they look dashed, but print as solid.
Then I tried to raise the compatibility in the export settings of Indesign to "Acrobat 8/9", but no chance. However, printing the document directly from within Indesign brings the expected result.
So it's definitely a bug of Acrobat.