Linux crashing...kernel panic

hey list,
this is very urgent and requires a quick response. this query pertains to linux kernel crash which is happening very often and the messages I get at the screen is as follows:
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Unable to handle Kernel
NULL pointer dereference at Virtual address 00000004
Printing EIP: c014127f
*pde = 00000000
OOPS = 0002
smbfs binfrnt_misc cpqci autofs
PCmcia_core tg3 eepro100 usb_oh_ci usbcore ext3
cpu 0
EIP 0010: [<c014127f>] tainted: PF
EFLAGS: 00010286
EIP is at get_unused_fd [Kernel] 0x1f (2.4.18-3 smp)
eax 00000004 ebx f0212000: ecx 00000045 esi 00000002 edi 0808dd18
ebp 00000000 esp eededf8c
ds 0018 es 0018 ss 0018
Process (pid: 0 Spackage = (edcd000)
stack: 00000000 00000000 00000000 ffffffe8 f6212000 00000002
0808dd18 f6212000 c01413e0 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000   00000000 00000000 00000000 00000000 00000000
00000000 00000000
Call Trace: [<c01413e0>]sys_open [Kernel] 0x20
code: f0 812800 00 00 01 0f 85 39 04 99 8b 45 1c 31 f6 89 44 <0>
kernel panic: attempt to kill the idle task In idle task- not syncing
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the next day I got quite different messages on the screen i.e.;
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Vubbr_misc cpqci cpqasm cpqevt autofs pcmcia_core 8021q bcm5700 c100 usb-ohci
CPU 3
EIP : 0010 [<f888f1eb>] Tainted : P
EFIAGS : 00010246
EIP is at ext3_Orphan_add [ext3] Oxfb (2.4.18-35mp)
ear : 00000000    ebx : 00000000
esi : f583cb60     edi : fb4a7600
ds : 0018 es : 0018 ss: 0018

Process conf……. (pid : 28536, stackpage=f6 ad 9000)
stack :         00000000 f64a7600 d6986b60 f888d735 f64a7600 f888d746 e8e44120 00000000
       00000014 f6ad9f0c f40fc6a0 f6ad9f0c f40fc6a0 f888d947 f64a7600 f40fc6a0
       e3dec500 dfe7638o 0000002d 0000002d f1320ba0 00000000 f40fc6a0 d6986b60

Call trace :    [<f888d735>]    ext3_mark_itoc_duty [ext3] 0x27
               [<f888d746>]    ext3_mark_ilr_duty [ext3] 0x36
               [<f888d847>]    ext3_mark_inode_duty [ext3] 0x27
               [<f888f91d>]    ext3_unlink [ext3] 0x1cd
               [<e014ef157>]   ufs_unlink [kernel] 0x1b5
               [<<014d9aa>]    lookup_hash [kernel] 0x4a
               [<<014f020>]    sys_unlink [kernel] 0x9a
               [<<0108c6b> ]   system_call [kernel] 0x33

Code : 8b 80 e8 00 00 00 89 85 6c 01 00 00 8b 45 28 8b 96 14 01 00
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I doubt this is a driver upgrade issue but am not sure. can someone throw more light on this? This is quite a critical issue and needs to be fixed immediately.
I tried running ksymoops but no luck...
please guide...