Can someone help me? I have a lot of trouble in my designed structure with steel trusses on top of RCC columns

Research 2.std 

I designed a structure for our undergraduate research but i keep messing up with errors and warnings such as

-zero stiffness

-instability at joints

-member not supported

is my designed structure just not designed well or i can't combine steel design on top of a concrete design?

thank you for answering.