I've seen this issue too, with Windows 8. As the error message states, it is due to some issue with Windows 8. It works fine with Windows 7.
But the good news is the Windows 8 "Optimize" feature for SSDs does work for SSDs in a RAID 0 volume. The Windows Optimize option can be run from the disks Properties option, in the Tools tab. The Windows 8 Optimize/Manual TRIM feature works with any SSD.
Thank you parsec for your quick answer. I found the Windows 8 "Optimize". I did not know about it regarding SSD in RAID "0". I still would like Intel to fix the Intel SSD Toolbox so it can be done from the toolbox. Now I know I can do it with Windows 8 "Optimize". Thanks again.
We would recommend you to install the latest BIOS firmware for your motherboard, this way you can upgrade the RAID option ROM to a higher version of it and then proceed to download and install the latest driver for the Intel® Rapid Storage and Intel® SSD Toolbox.
Also, If you want to confirm that TRIM is enabled please follow the recommended steps at the following article: