CRM 4.0: Cannot delete or export an entity

We were recently confronted with a situation where we were trying to export customizations in our 4.0 environment but the export kept on failing. We narrowed it down to one troublesome entity. We even tried deleting this entity. But no matter what operation we tried (export, delete, publish), we kept on receiving the following unhelpful error message:

We ran a trace and various other standard troubleshooting operations but nothing pointed us in the direction of the error. I've seen this error in the past where an attribute that was deleted is still referenced from the form and the solution is to open the form and remove this artifact and then publish. This wasn't the case here. So were a little bit stuck.

We turned to Microsoft support who indicated that the issue was indeed related to a missing attribute. However we still were unable to locate the missing attribute even after performing a thorough check against each relationship and verifying that the lookup field was present in the list of attributes.

We were able to finally resolve this by installing an XML comparison tool that allows you to pick an entity that runs a comparison between what is found in the database and what is found in the list of attributes on the form. The tool found the missing field. And to resolve we added that field again to the entity at which point we were able to publish and perform all the usual actions associated with entity customization.

Microsoft have been a little cryptic about this tool that they used claiming that it is still "being developed" and therefore uninstalled it after performing the above troubleshooting.

However I was able to find the following post that seems to reference a similar tool (and includes a download option to boot). I guess we will only know for sure if/when we are faced with this issue again at another client installation.