Could you please let me know what version of MS Office are you using.
Is it compatible with Acrobat 9?
Try converting some other excel file to PDF and check if the same issue persists.
Have you tried using 'Adobe PDF' printer under File> Print to convert the file into PDF.
or check in your excel file whether Acrobat PDFMaker Office COM Addin is enabled under 'File> Options> Add-Ins> Manage(COM Add-ins)
Please check and then let me know.