Ok. I figured it out. The error was because I did not write the shipping rate lines properly such as:
0.82|6|P0, S0, C1
1.6|10|P0, S0, C1
3.3|13|P0, S0, C1
7.2|18|P0, S0, C1
once I wrote it properly. It worked. Thank you for providing this plug in.
Kawtar