If you are using the two built in script queries, "SNMP - Get Mounted Partitions" and "SNMP - Get Processor Information", you can migrate to the PHP Script Server using the steps below:
Verify the existence of New Data Input Method - Go to Data Input Methods, verify that you see the "Get Script Server Data (Indexed)" Data Input Method exists and that it is using the "Script Query - Script Server" method.
Disable the Poller - Goto Settings->Poller and uncheck the Poller Enabled checkbox. Press Save.
Update Your Data Queries - Go to Data Queries and Edit the two Data Queries below. Change both their Data Input Method to "Get Script Server Data (Indexed)" and in the XML path replace "script_query" with "script_server" as shown below:
SNMP - Get Mounted Partitions
SNMP - Get Processor Information
Update Your Data Templates - Goto Data Templates, locate the following two data templates and change their data input method to "Get Script Server Data (Indexed)".
Host MIB - Hard Drive Space
Host MIB - CPU Utilization
Re Enable the Poller - Go to Settings->Poller and check the Poller Enabled checkbox. Press Save.
Following those steps should complete your migration to the new PHP Script Server for the two example HostMIB Data Queries.