Hello,
I apppreciate the issues people are having and no doubt it is a big problem, however I thought I should repond with a few points
1. this is not strictly a DotNetNuke problem - the issue (I believe) is that internally the ajaxtoolkit changed from scriptmanager to toolkitmanager, and hence broke any asp.net ajax that assumes a scriptmanager (i.e. all telerik and other 3rd party asp.net ajax libraries- DotNetNuke sees this issue as we use telerik). I believe this means that you can use older versions of the ajaxtoolkit just not the latest one. Personally speaking I think ajaxtoolkit should have made the change configurable so users could use scriptmanager rather than toolkit manager, but it's also something DotNetNuke should do i.e. I agree with http://support.dotnetnuke.com/issue/V...
2. vb.net code is not useless, the only thing that changed was DotNetNuke's core code which you should not be editing as that effectively creates a fork and runs the risk of breaking upgrades. You may still code your extensions in either c# or vb.net.
3. we try to ensure that anything that works with asp.net works with DotNetNuke , there should are no code based barriers in DotNetNuke (beyond our existance on medium trust for security purposes) - It's not a question of what we support as we can't hope to have test environments for every asp.net plugin i.e. anything asp.net can use should work, if it does not please log an issue so we can evaluate
4. despite the popularity of this thread I don't see any issue raised for it on support.dotnetnuke.com (beyond the one I linked earlier) - we can only work on what we know about (despite my presence on this thread I am not working bugs at the moment, I am on the 6.2.0 team)
5. telerik (via the wrappers) are free to use for all users of DotNetNuke -it's only if you want access to the design time controls that you need a developer licence of telerik.
Thanks.