You should find Adobe Air at this locations:
Windows Vista and Windows 7 [64 bit] : C:\Program Files (x86)\Common Files\Adobe AIR\
Windows 2000, XP, Vista, and Windows 7 [32 bit]: C:\Program Files\Common Files\Adobe AIR\
If you have still problem try to reinstall Adobe Air maybe the AIR runtime/framework, maybe it wasn't properly installed.
Here below also two links for troubleshooting Air installation:
http://kb2.adobe.com/cps/403/kb403150.html ( troubleshoot Air installation)
http://kb2.adobe.com/cps/407/kb407625.html ( Determine what version is installed)