As I believe IMC is starting a Java Applet which is starting PuTTY (or any other terminal app).
You can change the path to PuTTY in this file:
/opt/iMC/client/web/apps/imc/WEB-INF/putty-devToolsConfig.xml
<pref.defpath>C:\Program Files\PuTTY\putty.exe</pref.defpath>
My question now is, how is this supposed to work when accessing IMC from a Mac. ;)