Welcome MetallicaF
ET can have problems with some larger maps resulting in "Hunk_Alloc failed on 656064...".
Check your
/com_hunkmegs in the console ~. If it is 56 set it to 96
/com_hunkmegs 96
then reload the map
(myself I have
seta com_hunkmegs "128" in my profile\TomTom\etconfig.cfg so it always gives me enough memory).
As to et_dam I have only found
et_dam_b1.zip which is an unauthorized conversion of the RTCW map. I'll download it to see what it is like. However I don't have the time to do more waypoints(navigation files) for many weeks or more. I am also reluctant to do unauthorized conversions. (unless very popular or some original work was included). So no promises.