NIS prevents me forwarding messages with attachments

I wish to forward messages with attachments received from some family members.  NIS prevents me doing this.

I have updated to 2012 version.  I have tried temporarily disabling the anti-virus protection and I have tried changing the NIS settings.  These solutions have not worked.

NIS did not do this earlier in the year but now it is systematic.

 

Can anyone help?  Thank you.