InfoPath Dev

I have an interesting situation.  I am using Office 2007 suite and installed the latest service pack (SP3) and now when I try to sign an InfoPath form, it tells me the signature is invalid.  "Before you can add a new signature, remove any signatures with invalid, error, revoked or not trusted signatures ...

I do use code on my form (I can't avoid it).  I can't attach my form for privacy reasons.  I had several other forms I created using InfoPath 2003 and upgraded to InfoPath 2007 and those can be viewed correctly in InfoPath 2003 still.  This one form in particular was created using InfoPath 2007 only; as it is a new form ...

I have designed a form in Infopath 2007 and I published to my moss site. My end users are still using Infopath 2003 and receive an error message that "InfoPath cannot open the form". "The form template was created by a newer version of InfoPath. This form template was created by InfoPath version 12.0.0" I have made all the ...