The obvious answer is: the userid and password do not match, so nothing is returned.
Use the debugger, to single step through your code and check exactly what is happening, and what is in the various variables.
But please, don't do that: Never store passwords in clear text - it is a major security risk. There is some information on how to do it here:
Password Storage: How to do it.[
^] - it's in C#, but the code is pretty obvious.