It looks like there is some process or service still running, and this is preventing the uninstall.

It seems to me you have two options;

1] Run Vista's System Configuration Editor, (Start > Search type in msconfig and press Enter), and in the Startup tab, find any entries for this web cam and remove the tick. Restart the system and then see if you can uninstall.

2] Restart the system into Safe Mode. In this mode only default drivers, processes and services are loaded, and then you can go to Vista's Control Panel > Programs & Features, and uninstall it from there.

Hope that helps.

Mark