I haven't dived deep into this, but most likely the loader exceptions happen because the assemblies you are importing require something more.
Try creating a standard .aspx page (on the same website) using the same controls and see if it works there. Probably you would still see the issue.
If you only have this issue when going through Composite C1 I'd suggest you upgrade to a recent release - I see that CompositeC1Contrib is part of the stack and we did some work on this area in 4.0, making the same bits part of the Composite C1 core. If you are running on these latest bits we can give better support.
Try creating a standard .aspx page (on the same website) using the same controls and see if it works there. Probably you would still see the issue.
If you only have this issue when going through Composite C1 I'd suggest you upgrade to a recent release - I see that CompositeC1Contrib is part of the stack and we did some work on this area in 4.0, making the same bits part of the Composite C1 core. If you are running on these latest bits we can give better support.