Cannot Modify Agreement - Issue with Attachements

Hi,

I am attempting to send an Agreement with multiple attached documents, however when I 'Send for Signature' I received the following error message:

Cannot Modify Agreement
A recipient has signed, approved, or delegated the agreement. This agreement cannot be modified.

The strange thing is that I can 'Send for Signature' if I have NO attached documents with the agreement. but if I try to attach anything (doesn't matter what type of file) I receive this error message.

Has anyone experienced this?
Can anyone help me with getting passed this message?

Thank you,

Jackie