Can't boot 2.6.26-rt1

VFS: Cannot open root device
"disk/by-id/scsi-SATA_WDC_WD1600BEVS-WD-WXEZ07100576-part 7" or
unknown block(0,0)
Please append a correct "root = " boot option; here are the available
partitions.
Pid:1,comm:swapper Not tainted
2.6.26-rt1-default#1linux-rt-users@vger.kernel.org
[< ffff ffff 8046 c149 >] rt_mutex_lock+0x22/0x50
[< ffff ffff 8046 cae6 >] _mutex_unlock+0xe/0x10
[< ffff ffff 8020 cb00 >] exit_intr+0x10/0x1e
[< ffff ffff 8028 633d >] trace_hardirqs_on_caller+0x1e/0x133
[< ffff ffff 8020 d608 >] child_rip+0xa/0x12
[< ffff ffff 8020 cb69 >] restore_args+0x0/0x30
[< ffff ffff 8020 d5fe >] child_rip+0x0/0x12

preempt count 00000001
1-level deep critical section nesting
[< ffff ffff 8047 43e2 >] .... panic +0x43/0x167
[< ffff ffff 8073 6338 >] (<= mount_block_root+0x258/0x26f