getphotourl problem

Hello,

I'm trying to get the photo url for a specific user using this api method: http://projects.zoho.com/portal/{PortalName}/api/private/xml/user/getphotourl?apikey=[ApiKey]&ticket=[ticket]

But I'm getting a "General Error", I'm passing the parameter userId, I have tried passing the values p_id and login_name returned by the method for getting all users from a project.

Am I missing something??

Thanks in advance