Here we go again. Using the latest April 2013 edition of AjaxControlToolkit 4.5 and I've done all the typical things we've seen over the past 6 months of getting it to work in our 4.5 projects. (changing the script manager, adding ajaxtoolkit to web.config, etc.)
Good news is, everything works wonderful locally. However, when deploying to IIS7 running 4.5 (well it's in there as 4.03 something) I'm getting that Tools Requires 4.0 error that we all love.
The issue is clearly at the server level since it works great in my environment locally. I'm using VS2012 and using a Web Application project. I'm using the publish mechanism to throw everything to the server, so maybe there's something it's not transferring there as well.
Been working on this for 4 hours last night and 4 hours so far today. Driving me crazy, so I figured I'd post this out there.
Ok got it. During a publish I checked the "Delete All Files" first and then did the publish. This must have finally wiped out the Ajax 4.0 things somewhere and then the app ran just fine.