domain mapping whmcs URL issue and not able to see domain mapping in Tools menu

Dear friends,

I installed domain mapping and configured it in two places i am not able to do it right

the Settings - Domain Mapping - (Reseller Options Tab) - whmcs
i am getting the following error
Looks like your credentials are invalid. Please, check the errors sent by WHMCS server:
A valid URL was not provided.
"the path of whmcs is"
my client registered a domain i am confused as to how to map the domain. because no subdomain is available relating to the above domain.
my client registered the domain through the whmcs installation - but a subdomain was not created.

Now i have two issues :
1) the whmcs path setting
2) how to get the subdomain registered (i seem to goof up somewhere)
Please Advice,

Best regards

Srinivas Peesapaty