The leading / means that it will look for /modules/commands.so (obviously wrong). Without it, it will look in /path-to-Unreal3.2/modules/commands.co (obviously right).
I have sort of the same problem, the server was running fine, when it suddenly crashed and when i try to restart it, it says :
* unrealircd.conf:1: loadmodule src/modules/commands.so: failed to load: tmp/130182B5.commands.so: undefined symbol: m_svsfline_Init
there is an m_svsfline.c in the module dir, but no .so could it be that ?
not really 100% relavant to the subject, just an observation, it looked to me like from your post you were loged in w/ root , and its (corrrect me if im wrong) generaly not the best policy to run the ircd from the root account, it would be best to make a less privelaged account and run your ircd from there
To Gotisch: Could you please recompile (=reinstall?) your ircd and find out whether the problem disappears? I think it's just a problem with mixing binary files (for example, a new compilation of ircd with a previous compilation of commands.so).