High,
i dont know what OTM is but i think this is a normal HP OV problem.
look under HP-OV -> Options -> Event Configuration if there are trap entrys from the OTM system (only if you have loaded the corresponding MIB Files, if not do so!). Look fot the missing traps and make sure that they are not set to "log only" or "dont log or display". you should also set the right trap receiver (your HPOV system) on the otm system. If this all cant help you use snoop or truss to see what kind of traps OTM sends and what your HP OV system is receiving.