I can't import your addon. Getting stuck at installation:
http://puu.sh/8HTDb.png
EDIT: Although it stucks, i can set mass PM usergroups in admicp. BUT when i click on New Message i get
Parse error: syntax error, unexpected 's' (T_STRING) in /home/ehcainho/public_html/forum/includes/class_core.php(4715) : eval()'d code on line 83
and this no content
http://puu.sh/8HTRq.png