Hey all. The fix is up now and you should be able to save monsters that you've leveled and import and save custom monsters from the classic Monster Builder. It looks like some of you bumped into some issues while we were pushing the fix, but hopefully all those are over.
Now on to the topic of "why did you release something that wasn't feature complete?" questions/complaints. Main reasons, short and sweet - we wanted to give all the DDI members a chance to check out what we're working on, and we wanted to make sure that all DDI members had the chance to use the MB to import monsters into their VT games during the next step of the VT beta.
You still have access to the classic MB (you can download it right now). We won't be doing any more updates to it, but it's still there and still usable. Yes it has issues, but I'm hopefully most people understand that we won't be working on the old tools while adding features to the new tool. With the web-based MB, we have something that gives very basic functionality and is usable with the VT that we wanted to get into everybody hands, not just the small group of testers that we had before.
The VT point is a bit more tangible - Having the web-based MB out, even in this limited form, makes imputing monsters into the VT 1000% (statistic completely made up) better for DMs. So getting this out to DDI subscribers who will very soon be testing out the VT seemed a pretty important thing.
I am definitely sorry that I haven't given you more news on what to expect with this AT release these last few weeks. I'm also sorry if I led you to believe that the AT would be more robust than what the closed beta testers had access to. We did add a couple features, but the biggest changes are on their way. I will be back in the coming days with more information on the features we'll be implementing, focusing on whatever the next big thing is.