FormatCDRW doc, hope it (sort of) helps:
Requirements: CD or DVD RW drive with Packet-Writing support, perferably Mount Rainier compatible, special filesystem (SFS 1.196+).
Change the DEVICE and UNIT tooltypes of the Storage/DOSDrivers/(CD|DVD)(M)(+|-)RW dosdriver(s) to the ones of your CD/DVD writer. Use CDMRW if you have a Mount Rainier compatible CD-RW drive, DVDMRW if you have a Mount Rainier compatible DVD+RW drive.
CDRW and DVD+RW drives with Mount Rainier support:
Use the CDMRW or DVDRW mountlist and use "Format MRW" for formating. MRW background formatting can be stopped and restarted with "Stop formatting" and "Continue formatting", manually restarting an inclomplete MRW format is not required, it will be done automatically by the drive.
Drives without Mount Rainier (MRW) support are supported as well, but don't write often to a CD/DVD, remeber that they can only be overwritten about 1000 times and without MRW there is no defect management, i.e. the first bad sectors makes the compelete CD/DVD unusable already.
-CDRW: Use the CDRW dosdriver, the usable size of a 650 MB CDRW is about 450 MB. If the CDRW is not empty you have to use "Blank" first.
-DVD-RW: Use the DVD-RW dosdriver, the usable size is about 4.383 GB. Using "Blank" is not required. Warning: Formating a DVD-RW takes a lot of time and can not be interrupted.
-DVD+RW: Use the DVD+RW dosdriver, the usable size is about 4.376 GB. Using "Blank" is not required and like with MRW formatting is done in background and can be stopped and restarted anytime.
Don't use a CDRW/DVD-RW/DVD+RW like a hardisk, it isn't and can't be, and only store large files, for example (backup) archives, not something like a unarchived icon collection

If you need something which works like a removeable HD get a MO or DVD-RAM drive instead, MO and DVD-RAM media can be overwritten several millon times.
If something doesn't work please start "FormatCDRW >log debug" in a shell, do it again and attach the log file to your bugreport.