oops on ISN load in 2.5.56

Hi.

I've been trying out 2.5.X, and I get an error on loading the drivers for my passive HFC-PCI card.

Any thoughts?

Unable to handle kernel NULL pointer dereference at virtual address

00000028
printing eip:
cc867c91
*pde = 00000000

Oops: 0000
CPU:    0
EIP:    0060:[<cc867c91>]    Not tainted
EFLAGS: 00010002

EIP is at get_drv_by_nr+0x31/0x337983a0 [isdn]
eax: 00000000 ebx: 00000010 ecx: 00000007 edx: 00000023
esi: c7d00000 edi: 00000202 ebp: cc890f87 esp: c7d01ef8
ds: 007b es: 007b ss: 0068
Process perl (pid: 1002, threadinfo=c7d00000 task=c7cff940)

Stack: 00000001 00000538 cb963ec0 cb963ea0 00000000 00000000 00000023
cc868904
       00000023 cc873136 c7d01f40 c01afddf cb963ec0 cb963ea0 cc890f88
cc8689cc
       00000000 cc87312f 00000000 00000000 00000000 cb963ec0 cb963ea0
cb963ea0
Call Trace:
 [<cc868904>] get_slot_by_minor+0x14/0x33797710 [isdn]
 [<cc873136>] +0xd2a/0x3378dbf4 [isdn]
 [<c01afddf>] sprintf+0x1f/0x30
 [<cc890f88>] istatbuf.3+0x8/0x3376f080 [isdn]
 [<cc8689cc>] isdn_statstr+0x4c/0x33797680 [isdn]
 [<cc87312f>] +0xd23/0x3378dbf4 [isdn]
 [<cc869069>] isdn_status_read+0x79/0x33797010 [isdn]
 [<c014b08e>] vfs_read+0xbe/0x130
 [<c014b32e>] sys_read+0x3e/0x60
 [<c010b20b>] syscall_call+0x7/0xb

Code: 8b 43 18 40 89 44 24 0c 8b 43 18 89 44 24 08 8b 03 c7 04 24