does your 'esp_sys.pbo' have a pbo-prefix of 'esp_sys' ?
if so, in your config.cpp in the esp_sys folder, having...
scriptsPath="esp_sys\events\";
should work... in your first post, you state the default scripts path as...
scriptsPath="scripts\";
which is, true, to and extent... but, as soon as ui.pbo gets read by the game... it gets overridden by...
scriptsPath="ca\data\scripts\";
which stills points to the place you mentioned...
however, if you are running, this 'esp_sys.pbo' in the main addons folder, and trying to set 'scriptsPath' to something it will be getting overriden by ui.pbo's version...
you'd have to run 'esp_sys.pbo' in a 'mod' (for instance)...
<ArmAInstallationFolder>\Terox\AddOns\esp_sys.pbo
and the 'pbo-prefix' inside would have to be 'Terox\esp_sys' and the path for 'scriptsPath' would need to be...
scriptsPath="Terox\esp_sys\events\";
and you'd have to fire up ArmA with '-mod=Terox'
i think... i'd have to check it myself to be sure... but, it'd be something along those lines...
PS. releasing 'ca.pbo' as part of your 'mod' would be... hmmm... a little nuts!