First, if you have Pro Tools M-Powered Essential, you can't run other plugins than what's been bundeled with your device.

ARIA Player (or chipsounds) come as a Multichannel/Stereo plugin in Pro Tools, not as a multi mono (it cant run in mono)

Under Mac OS X
1)Check to see if you've got ARIA Player installed in here:

/Library/Application Support/Digidesign/Plug-ins/ARIA Player RTAS.dpm
And not in
/Library/Application Support/Digidesign/Plug-ins (unused)/

2)make sure you select it in this structure:

Under Windows
1)Check to see if you've got chipsounds installed in here:

C:\Program Files\Common Files\Digidesign\DAE\Plug-Ins\Aria Player RTAS_x86.dpm
And not in
C:\Program Files\Common Files\Digidesign\DAE\Plug-Ins (unused)

NOTE: there is a bug in the chipsounds 1.0 installer where we place the RTAS (dpm) file into "Common Files" _regardless_ of the language of your operating system... you will need to move it.

2)make sure you select it in this structure:

If the files are in the right place and you DONT see your ARIA Instrument in that SAME menu, please send us your logs.