Ok, so the problem is that PSim trail version does not allow you to have more than 1 input and 1 output while yuou perform a co simulation with simulink. The problem is enhaced further by the fact that only 6000 data points can be stored with the trial version. Here is the solution

1. Download the trial version of PSIM and install it.
2. After installation check if the Sim Coupler blockset is available in SIMULINK or not.
3. If it is available then uninstall the PSIM.
4. Download the cracked version of PSIM.
5. Unzip the files
6. Copy the following files
1. PSim dialog.fig
2. PSim dialog.m 
3. Set Sim Path
4. Sim Coder.dll
5. simcoupler.dll
6. simcoupler.mexw32
7. Paste it in the following folder of MATLAB. My target folder is given as                          C:\Program Files (x86)\MATLAB\R2009b\toolbox\simulink\SimCoupler