I am concerned that you are referencing the .FRC file AND time history analysis in CAESAR II.
The .FRC file provides time history data to CAESAR II which is then converted (in CAESAR II) to a force response spectrum. That force response spectrum is intended for response spectrum analysis, not time history analysis. Unfortunately, this force response spectrum data format is similar to the time history format. The program will improperly interpret your force response spectrum data as time history data if you present it so. Do not do this.
Check your dynamic input!