Under RISC OS 3.1 partitioning drives is not necessarily straight forward. The program Setup (the piece of software that manages the SCSI card and attached drives) does not allow the last partition of a drive to be greater than 500Mb. So that means that if you have a 1010Mb HD and wanted to split it in half (505Mb each, you would end up with 505Mb + 500Mb - not what you wanted.
As it is, there is no way to change this, and the responce from CT is that there are not going to alter the operation of Setup in this circumstance. The onyl thing to do is to ensure that the last paritition on any drive, is 500Mb, or less.
It must be noted that this 'feature' is only limited to the partitioning program Setup. SCSIFS, SCSIHandler and SCSIFiler modules will handle partitions upto the limit supported by the Operating System. In the case of RiscOS 3.1, this is 512Mb