While working with mm_forum you could face some problems. It seems to me that they are more or less common.
Setting up a cronjob for indexing the search is quite easy. You can do it like this
-*/15 * * * * user Lynx "http://www.domain.tld/forum/search.html?tx_mmforum_pi4[ind_auto]=1 &tx_mmforum_pi4[indexingPassword]=admin" –accept_all_cookies > /dev/null
But it is recommended, that you change the password before starting the script. In the mm_forum-manual it is written: "It is strongly advised that you change this password to another value of your choice". Because it is a security-risk.
You may look for a free md5 hash service in the web. There you get a hash code for your password. Afterwords you change the cron-rule: change "admin" to whatever you calculated.
Apres you must change the default-password either with constants-editing or Typoscript-rule:
"plugin.tx_mmforum.indexingPassword = 21232f297a57a5a743894a0e4a801fc3;"
Adding avatar failed
User could not add an avatar image to their profile. An update to mm_forum 1.9.2 solved this problem.
Self Registration failed
I an user self registrates, the user was added to the system but could not login. An Update to mm_forum 1.9.2 solved this problem to, which was caused by a false entry to the flag "bind to domain".