BIOSconfig must be run as root (Linux, Solaris) or Administrator (Windows) because it needs to use drivers that are in read and write protected physical address space.
For Solaris, see: How to Obtain the BMC Driver
Linux versions of BIOSconfig also depend on access to /dev/nvram to guarantee serialized access to the CMOS. RHEL4 distributions do not seem to include this device by default, RHEL5 and SLES do. To use /dev/nvram, the driver needs to be compiled into the kernel (or loaded as a module), and /dev/nvram must exist (root can create it using mknod /dev/nvram c 10 144).