vendor site api error : he operating unit is either invalid or it cannot be derived. Please verify y

Hi,

When I try creating vendor site using api, I get below error:

Unable to process your transaction. The operating unit is either invalid or it cannot be derived. Please verify your Multi-Org profile options.

Operating Unit Info is null

api used is "ap_vendor_pub_pkg.create_vendor_site"

Any pointers would be appreciated. I tried checking profile options MO:Security profile and MO:Default Operating Unit and MO:Operating unit , but no luck so far.

Jazz