On a virgin Intel P4 machine with winXP,  using  Csound5.07-win32-f.exe 
freshly installed, 5.07 is not behaving as expected - so do forgive 
me, folks, as I ask for advice or suggestions. 

Csound seems not to find portaudio as a driver option. 
Probably a simple but frustrating missing PATH issue for me. 

When running /examples/am.csd in Csound5GUI, a warning and an 
error are reported; 

WARNING: csould not open library 'C:\Program Files\Csound\plugins\rtpa.dll' 

and 

ERROR: unknown rtaudio module: 'PortAudio' 
Failed to initialise real time audio input

when PortAudio is selected in Csound5GUI Configure. 
No error or warning when MME is selcted. 

Running Csound from the CMD prompt, reports 
.. Cannot find C:\Program Files\Csound\plugins\rtpa.dll. 
rtpa.dll is there in the \plugins directory. 


Following advice from Michael or Davis Pyon, the present situation is 
that I have renamed portaudio_x86.dll to portaudio.dll, which is in the 
Csound\bin directory. 

Control Panel -> System Properties -> Environment Variables 
presently contains; 

User Variables for user; 
PATH   C:\Program Files\Csound\bin

System Variables;
OPCODEDIR   C:\Program Files\Csound\plugins
PATH    [.....]; C:\Program Files\Csound; C:\Program Files\Csound\bin;