'Font contains bad/Widths' and 'Cannot find/create font' errors when saving pdf as Other > Reduced Size PDF

I am exporting .indd files from within Indesign as pdf files, opening in Acrobat Pro XI. I have no trouble creating the initial pdf file, however, when I go to Save Other > Reduced Size PDF I get error messages. Depending on the file, I receive either the message, "The font (Myriad Pro) contains bad/Widths" replacing the text with dots or "Cannot find or create the font (Helvetica) Some characters may not print or display properly" replacing text with dots or boxes.

My confusion is that the file is exporting to pdf from Indesign without error, it is only when I try to Save Other> Reduce Size PDF that the error occurs.
Also, it is only occurring on five out of 120 pages. These same fonts are on other pages and I have no trouble at all with exporting or Reduce Size PDF.
More frustrating is that I have never had this problem occur in all my previous versions of Acrobat using the same process and typefaces.

I am reaching deadline on this and cannot find a solution other than to reload Acrobat 9 and ditch this upgrade.

Any help would be greatly appreciated.