/bin/bash on both RH 6.1 and 6.2 is bash1, while MAKEDEV sometimes uses features introduced in bash2. In particular, the current implementation of first() and second() in MAKEDEV really needs bash2 (and without it devices like /dev/sdaa cannot be properly created) Also, while not being a bug, it could be that when creating /dev/sdaa* you didn't mean to create /dev/sdaa and /dev/sdaa[123] only (for sd[a-z] you create /dev/sd?[12345678]).
Both of these items will be fixed in MAKEDEV-2.5.3-1 and later in Raw Hide (ftp://ftp.redhat.com/pub/rawhide/i386/RedHat/RPMS/). Please reopen this bug ID if an upgrade does not resolve either of these.