ERROR: Expected a number object when trying to organize pages

[Teri5EA5]

I've done it before but suddenly while trying to delete pages from a pdf I get this error message. "EXPECTED A NUMBER OBJECT"   

Using Adobe Acrobat Pro

I've uninstalled and reinstalled program.

Any ideas?

[Thom Parker · Accepted solution]

Acrobat is not the problem, the PDF has been corrupted. 

[Teri5EA5]

Thank you Thom.  I'll try a different pdf and see how that goes.