Verify a CRM Account Exists

Verify a CRM Account Exists

I am trying to send a POST to see if an account exists by Account Number. I absolutely have to use the Account Number field in my query. This is what I am sending:

http://crm.zoho.com/crm/private/xml/Leads/getSearchRecordsByPDC?newFormat=1&apikey=myapi&ticket=myticket&selectColumns=Accounts(Account Number,Account Name)&searchColumn=Account Number&searchValue=114011476211611

Zoho responds with:
4420 Invalid Search Column.Check it now