I recently ran into a recurring issue, and having searched the forums, I did not find any solutions.
It is understood that WPMUDEV will not Support GForms any more than Ford will not support Chrysler
So the issue is that the new blog templates created sites will not have the ability to save forms. The fix is pretty easy.
I created a template site, say #100 - as templating the main blog in multisite is a bad idea for many plugins.
I do not have gravity forms enabled on that, but I once did. Who knows if this is messing it up or not, however, I disabled all Gravity form related plugins on the template site.
Then I went in through network admin, and changed the version of Gravity forms under the EDIT site section. Ie, if its 1.6.5, I said 1.6.4.
As long as you dont touch the template, it will hold. Then any new site created off that template you can go in, activate gravity forms, and it works just fine.
Note, I have a global Key in my Wpconfig file for Gforms, but it is not network activated. I use pro sites to enable the possibility of use of plugin.
I am sure if i update gforms on the network, I will need to go back in and change my template site, however, this is a quick fix for anyone suffering problems I wanted to share with you Wpmudevvers.