EDIT: EDIT: I FINALLY DID solve it. The problem was rules on the fields that looked like this: [Condition: CheckBox {is equal to} "true"] THEN [{set} Read Only]
I guess it is redundant anyway, since the XML file is not writable by the form anyway (since it is a "receive data" source). I can't BELIEVE this little thing has caused me so much TROUBLE! How do you guys deal with developing in Microsoft Land all the time?
Anyway, thanks to anyone who read this with the intention of helping!
I am keeping my previous edits intact, for anyone who is interested:
EDIT: I did not solve it. For some reason, I thought that was working, but it was not. Here is what I posted when I thought it was working:
Never mind. I solved it.
The issue I was having was caused by my using a secondary XML data source as such:
1. There are two types of fields in the datasource, and, I must admint, I am no XML expert and probably needed a schema. Anyway, there are true/false fields and "xhtml" fields.
2. When a checkbox is checked (which is bound to one of the true/false fields in the XML file), it changes a "Rich Text Box" which is linked to one of the xhtml nodes, from "Hidden" to "read only".
This was causing a problem, for some reason. It worked fine in the InfoPath client, but I got that error when trying to publish to the web. The design checker didn't catch this, but would throw the above error, also, when run.
I don't know if this will help anyone, but my solution was to create the true/false fields in the main datasource and bind the checkboxes to them. This seems to have fixed the problem.
--mobrien118