AICA is the abend code for CICS/TS runaway program – program running for longer than the runaway time setting which is a PARM on the system initialization table (SIT). This means that the program ran for too long WITHOUT GIVING UP CONTROL. (too long being defined by the parm in the SIT.
I am not sure how the START command comes into play. Unless you began to use the START command with a new version of CICS, which might explain how and why the SIT value changed.