Spent the day investigating the COM wrapper that fails registering on several systems.
It seems that on some XP with IE6 the COM registration works, on a XP wit IE7 it fails, on a Windows2003 with IE7 it fails, on a clean Vista with redistributables installed it fails and on another Vista with development tools installed it works.
On the tested systems tried with VS2005 installed, also with VS2008, tried also with installing VS2005 and 2008 redistributable.
Investigated also with dependency walker the missing libraries but no clear result obtained yet. Tried also copying the missing dll files in the application folder but obtained no solution yet.