I'm not sure what's going on with that first error. My gut reaction is that it deals with a mesh, and with there being too many different elements in particular. Maybe that's because I recognize "element" as the term used for each of the separate UV groups, but it gives you somewhere to start.
The second one throws me for a loop. I don't know what "FixedArray" refers to, but it's clearly too large. Perhaps this deals with the first error in some way?
The final error deals with an ability you've created. The buff type indicates there should only be a single target, and you've either set it up as having no specific target or multiple targets.
The enum value conversion crap is really irritating. It means you have some part of your coding that's incorrect, but it could be any number of sources. For instance, you could have used the wrong letter case (lowercase where uppercase is required, for instance), you could have a typo due to mispelling or even a totally incorrect value, or you could have a blank space where a value is needed. In your case, you've probably just mistyped something in those stacking limit lines. Double check them against stock Sins files to make sure each part matches exactly. You could also check out a tool that ZombiesRus5 is putting together, which helps with entity validation. Here's the link.
Good luck with your corrections!