Hi Shumifan50,
After trying many different things to get my config working, I am happy to say your plugin works with a Geovision GV800 card running on Ubuntu with Zoneminder with all CCTV cameras visible.
It took me all week trying other methods including streaming from the server with vlc which worked too but slowly for the dreambox, then by chance I found a post for geovision single jpeg mode and thought I would give it a go and sure enough it works.
Only one change to my previous URL and config the word "single" instead of "jpeg".
Like below:
Code
{command}{foscam1.snapshot}{/cgi-bin/nph-zms?mode=single&monitor=16&user=admin&pass=admin}
{command}{foscam1.protocol}{http://}
{command}{foscam2.snapshot}{/cgi-bin/nph-zms?mode=single&monitor=22&user=admin&pass=admin}
{command}{foscam2.protocol}{http://}
{command}{foscam3.snapshot}{/cgi-bin/nph-zms?mode=single&monitor=20&user=admin&pass=admin}
{command}{foscam3.protocol}{http://}
{command}{foscam4.snapshot}{/cgi-bin/nph-zms?mode=single&monitor=21&user=admin&pass=admin}
{command}{foscam4.protocol}{http://}
{camera}{192.168.1.120}{foscam1}{Gate}{admin}{admin}
{camera}{192.168.1.120}{foscam2}{Pool-Garden}{admin}{admin}
{camera}{192.168.1.120}{foscam3}{Front-Door}{admin}{admin}
{camera}{192.168.1.120}{foscam4}{Side}{admin}{admin}
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More info here: http://www.zoneminder.com/forums/viewtopic.php?f=9&t=18939