You have to format the Hard Drive that you put in your Thecus- and you have to format it in FAT32 mode. This has to be done from a PC. As most people use XP, you should know that XP won't format a partition in FAT32 over 32GB.
There is a workaround to this (which I have used successfully on this device). This can be found at:
I have to admit, I went thecus cause I thought it was a great price, but I also found the manual very obscure.
Then i found freedom9's version of a nas...MAN. It's faster, quieter, sexier and cheaper! It's a 4 bay sata II machine that can do all the raids (including 10). Check it out, it's also got a slick backup utility.