Workspaces and versioning is one of those areas in Typo3 where a user is likely to stumble across many of Typo3's error messages. Well, like I say in the header below, at least I think they are all related to Workspaces and Versioning. Of all the things that have little documentation in Typo3... errors basically have none.
Because of this, I thought I'd include an area devoted to errors you might receive and troubleshooting.
If you come across an error not listed here, please if you can take a screen shot of it, jot down what you were doing and send them along, I'll add them.
As I worked with Draft/Live/Custom versions to prepare this section, I often worked with the Typo3 interface open in two browsers. That way I could have the content element open that I was working on as well as the section of Typo3 that I was working on.
I noticed that if I was in Draft on one and Live on the other, the two would get confused. It seemed once I did that, save in both, that I could not publish and could not swap in either live or Draft (You have to publish, swap versions from the version you created it in).
My recommendation is that you avoid having Typo3 open twice. I pay the price (loosing lots of text and having to redo sections) but would hate for you to.