It's right there in the rom browser...
Region issue - fails@level1; use (E) rom
I don't see that in mine, and i have the U version. Works fine as well.
Edit
Thats because its fixed.
[04DAF07F-0D18E688-C:45]
Good Name=Duke Nukem - ZER0 H0UR (U)
Internal Name=DUKE NUKEM ZERO HOUR
RDRAM Size=8
Counter Factor=1
Save Type=First Save Type
CPU Type=Recompiler
Self-modifying code Method=Protected Memory
Use TLB=Yes
Linking=On
Reg Cache=Yes
Use Large Buffer=No
Status=Compatible
Delay SI=No
SP Hack=No
Core Note=
Plugin Note=
Audio Signal=No
Cheat0=50000F04 0000,811CB960 0000 //Neko's 1st level freeze fix
Clear Frame=2
Resolution Width=-1
Resolution Height=-1
OP, download the latest unofficial RBD.