Same problem here with Hercules Blog Webcam on Karmic Koala.

Maybe, because kernel-header file gspca.h has NULL byte size??

Tested on up2date karmic with all updates.

compile errors from:

root@chaotiker87:~# module-assistant a-i ov51x-jpeg
# Build the module ▒
 │ /usr/bin/make KERNEL_DIR=/usr/src/linux KDIR=/usr/src/linux ▒
 │ KVERS=2.6.31-14-generic ▒
 │ make[2]: Betrete Verzeichnis '/usr/src/modules/ov51x-jpeg' ▒
 │ /usr/bin/make -C /usr/src/linux M=/usr/src/modules/ov51x-jpeg modules ▒
 │ make[3]: Betrete Verzeichnis '/usr/src/linux-headers-2.6.31-14-generic' ▒
 │ CC [M] /usr/src/modules/ov51x-jpeg/ov51x-jpeg-core.o ▮
 │ /usr/src/modules/ov51x-jpeg/ov51x-jpeg-core.c: In function ▒
 │ ‘create_proc_ov511_cam’: ▒
 │ /usr/src/modules/ov51x-jpeg/ov51x-jpeg-core.c:677: error: implicit ▒
 │ declaration of function ‘info’ ▒
 │ /usr/src/modules/ov51x-jpeg/ov51x-jpeg-core.c:681: error: ‘struct ▒
 │ proc_dir_entry’ has no member named ‘owner’
/usr/src/modules/ov51x-jpeg/ov51x-jpeg-core.c:681: error: ‘struct ▒
 │ proc_dir_entry’ has no member named ‘owner’ ▒
 │ /usr/src/modules/ov51x-jpeg/ov51x-jpeg-core.c:689: error: ‘struct ▒
 │ proc_dir_entry’ has no member named ‘owner’ ▒
 │ /usr/src/modules/ov51x-jpeg/ov51x-jpeg-core.c:700: error: ‘struct ▒
 │ proc_dir_entry’ has no member named ‘owner’ ▮
 │ /usr/src/modules/ov51x-jpeg/ov51x-jpeg-core.c:712: error: ‘struct ▒
 │ proc_dir_entry’ has no member named ‘owner’ ▒
 │ /usr/src/modules/ov51x-jpeg/ov51x-jpeg-core.c: In function ▒
 │ ‘proc_ov511_create’: ▒
 │ /usr/src/modules/ov51x-jpeg/ov51x-jpeg-core.c:766: error: ‘struct ▒
 │ proc_dir_entry’ has no member named ‘owner’
/usr/src/modules/ov51x-jpeg/ov51x-jpeg-core.c: In function ▒
 │ ‘ov51x_clear_snapshot’: ▒
 │ /usr/src/modules/ov51x-jpeg/ov51x-jpeg-core.c:1691: error: implicit ▒
 │ declaration of function ‘warn’ ▒
 │ /usr/src/modules/ov51x-jpeg/ov51x-jpeg-core.c: In function ▒
 │ ‘ov51x_v4l1_ioctl’: ▒
 │ /usr/src/modules/ov51x-jpeg/ov51x-jpeg-core.c:6386: warning: passing ▒
 │ argument 1 of ‘video_usercopy’ from incompatible pointer type ▮
 │ include/media/v4l2-ioctl.h:298: note: expected ‘struct file *’ but ▒
 │ argument is of type ‘struct inode *’ ▒
 │ /usr/src/modules/ov51x-jpeg/ov51x-jpeg-core.c:6386: warning: passing ▒
 │ argument 2 of ‘video_usercopy’ makes integer from pointer without a cast
include/media/v4l2-ioctl.h:298: note: expected ‘unsigned int’ but ↑
 │ argument is of type ‘struct file *’ ▒
 │ /usr/src/modules/ov51x-jpeg/ov51x-jpeg-core.c:6386: warning: passing ▒
 │ argument 4 of ‘video_usercopy’ makes pointer from integer without a cast ▒
 │ include/media/v4l2-ioctl.h:298: note: expected ‘v4l2_kioctl’ but ▒
 │ argument is of type ‘long unsigned int’ ▒
 │ /usr/src/modules/ov51x-jpeg/ov51x-jpeg-core.c:6386: error: too many ▒
 │ arguments to function ‘video_usercopy’ ▒
 │ /usr/src/modules/ov51x-jpeg/ov51x-jpeg-core.c: At top level: ▒
 │ /usr/src/modules/ov51x-jpeg/ov51x-jpeg-core.c:6651: warning: ▒
 │ initialization from incompatible pointer type ▒
 │ make[4]: *** [/usr/src/modules/ov51x-jpeg/ov51x-jpeg-core.o] Fehler 1 ▒
 │ make[3]: *** [_module_/usr/src/modules/ov51x-jpeg] Fehler 2 ▮
 │ make[3]: Verlasse Verzeichnis '/usr/src/linux-headers-2.6.31-14-generic' ▒
 │ make[2]: *** [all] Fehler 2

root@chaotiker87:~# lsusb
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 003: ID 046d:c00e Logitech, Inc. M-BJ58/M-BJ69 Optical Wheel Mouse
Bus 004 Device 002: ID 0518:0002 EzKEY Corp. EZ-9900C Keyboard
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 004: ID 06f8:3002 Guillemot Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
root@chaotiker87:~# tail -f /var/log/messages
Nov 20 19:56:49 chaotiker87 kernel: [ 2441.072031] usb 1-8: new high speed USB device using ehci_hcd and address 4
Nov 20 19:56:49 chaotiker87 kernel: [ 2441.206278] usb 1-8: configuration #1 chosen from 1 choice

root@chaotiker87:~# ls -al /usr/src/linux-headers-2.6.31-14-generic/include/config/usb/gspca
total 8
drwxr-xr-x 2 root root 4096 2009-11-15 15:19 .
drwxr-xr-x 38 root root 4096 2009-10-22 23:23 ..
-rw-r--r-- 1 root root 0 2009-10-16 20:09 conex.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 etoms.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 finepix.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 mars.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 mr97310a.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 ov519.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 ov534.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 pac207.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 pac7311.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 sn9c20x.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 sonixb.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 sonixj.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 spca500.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 spca501.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 spca505.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 spca506.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 spca508.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 spca561.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 sq905c.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 sq905.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 stk014.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 sunplus.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 t613.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 tv8532.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 vc032x.h
-rw-r--r-- 1 root root 0 2009-10-16 20:09 zc3xx.h

What happend to the header files?