In your screenshot I see two things that could be an issue.
1. You only really need the ‘post’ and not the request. You post the data to the php file, the php file executes and outputs any data that you want returned. That returned data will be in ‘Ajax.lastdata’. The way you currently doing it with two php files can work if preferred but you will still need to check the lastdata from the first post request in order to validate it was successful before doing the 2nd request.
2. The post request appears to be sending the parameters via a GET, are you receiving them via GET or POST in the php file?
If you use chrome, hit f12 and look at console & network, console will show any errors and network will show the two requests, the parameters and the returned data (if any)