Hi,
First of all, check the PDF producer of your form. Open Form in Acrobat -> Go to File -> Properties -> Look for PDF Producer in "Description" (Tab).
1. If your form is created by Acrobat then Reader XI should be able to save the form.
2. If it is created by LC Designer then you need extend the rights for Reader in the form.
For Acrobat 9 Pro --
Go to Advanced > Extended Features in Adobe Reader
Regards,
Anoop