I keep running into the same error on a recent project - the error message is "Some rules were not applied. The parameter is incorrect."
InfoPath returns this message when you try to set a value in a data source that has not been queried - so, let's say you have a data connection that does not query on load, and you have rules that execute the data connection that have conditions on them. Sometimes the data connection is executed, sometimes it is not. If you have other rules that may set a value in a field in that data connection make sure you check for the presence of the field or group first.