Sorry to hijack the thread, but I am having a similar issue. IP 2007 form built on a SQL DB as the main data source and published to a SP forms library. There are several other secondary data sources connected to the form. When I run the form from my local machine, no problems. When I go to the SP forms library and 'fill out a new form', no problems. When I go to another machine, log in as me (or anyone else for that matter) I get this error:
The query cannot be run for the following DataObject: Main connection
InfoPath cannot run the specified query.
InfoPath cannot connect to the data source.
InfoPath has encountered an error.
The operation failed.
I have tried a multitude of things to overcome this problem to no avail. Any assistance would be greatly appreciated. I have come a long way on this form and this is the last step (outside of a bit more QA) before production and I am dead in the water. I am not sure that I understand why deploying a form is so unblievably difficult!