Facing issues with post web api methods in Fitnesse

Hi,

 I am trying to use post web api in fitnesse but always returned with an error saying "An error has occurred: Call Web API" . I checked the java code for callwebAPI  which is being used and found that it is configured as exception message. I am not sure what exactly i am missing. If anyone had success in using post web api methods in fitnesse please share your experiences.

Thanks,
Ravi