Didn't able to debug my code!

Hi helpers !

I am working on a project of a fsm(Finite State machine) in which i have to detect 1100 sequence.

I done my coding but i didn't able to detect the starting sequence but my code can detect the rest of the sequence .

I am not able to debug my code or correct my code as i didn't able to figure out what is wrong with the code.

I provide screen shot of the code and the error i face in RTL STIMULATION.

Help me debug this error !!!!

{I didn't write any test bench as this project is given by my teacher and they said, you just have to write your logics and run RTL STIMULATION if your design is correct then you get congratulation message in RTL STIMULATION TRANSCRIPT .}