The dcdbas and dell_rbu drivers are Linux kernel drivers that are required to perform certain operations in libsmbios. For example, BIOS updates require the dell_rbu driver. These kernel drivers are included in the standard linux kernel starting with Linux 2.6.14. If you have this kernel and these drivers are not present, please talk to your vendor about enabling these drivers. For others on earlier kernels, there is a DKMS-based RPM containing these drivers that you can install. Here are the instructions:
The current DKMS drivers should work for all 2.6 and 2.4 kernels. Tested on RHEL3, RHEL4, FC4, FC3. Should work on others.