invalid_parameter_exception

Hi 

I am trying to call this API and showing me error. pelase let me know what is error. 

I am using IOMAD 3.8.+

I have pass parameter  like 

http://localhost/iomad/webservice/rest/server.php?wstoken=737a60f427555555825dd5b869f022e&wsfunction=block_iomad_company_admin_create_companies&moodlewsrestformat=json

companies[name]:ABCPvt Ltd

companies[shortname]:ABc

companies[city]:Pune

companies[country]:IN

companies[parentid]:0

companies[customcss]:''

ERROR IS : 

stdClass Object

(

    [exception] => invalid_parameter_exception

    [errorcode] => invalidparameter

    [message] => Invalid parameter value detected

)

Please correct me if I am wrong Here..........