I Have the exact same bug running Acrobat Pro CS5 on a MacBook with 10.6 snow leopard. I thought it was going to be an easy morning WhenI got up. Lol.
Are you trying to sign this PDF file on a file server share, a WebDAV share, or an MS SharePoint share? If yes, then copy the file to the local hard drive and sign the PDF document there. It should work on the local machine.
No. I am solo and doing this on my stand alone PC, I do not have any of those platforms that you mentioned. BTW, because of another technical glitch, I only recently – within the last month - re-installed Adobe on my local machine
John C Carrozzella, MD
Phone: (813) 659-2897
Fax: (888) 552-7536
Web: <http://www.hormonesandwellness.com/> www.HormonesAndWellness.com
Are you able to "Save as" your PDF without signing to the same location where you try to save it signed?