From iRed2 website:http://www.tinbert.com/iRed2/manual/lion
iRed2 V2.1 is running on Apple's latest Mac OS X 10.7 "Lion", however if your Mac is (now) starting in 64-bit mode and you are using a IRTrans USB, you'll need to upgrade the USB driver:
Unplug the IRTrans
Download driver from FTDI's page
Open package and install FTDIUSBSerialDriver_10_4_10_5_10_6
On my system it takes a little time "to optimize system performance"
No need to reboot!
Plug in the IRTrans USB