Just wondering as I couldn't find any data on this in Google.

When I load up my configuration at the initialisation of my program Log4Net gives me various entries that begin:

WARN: Duplicate Class Mapping...
or
WARN: Duplicate Collection role...

I was at first worried that this relates to another problem i'm currently having

http://nhibernate.sourceforge.net/forum/viewtopic.php?t=1596

however I tried deleting a different object that was apparently Duplicated in the mapping and that was fine.

Should I be greatly concerned over these messages or do they come as standard if you are doing a lot of mapping?
Apart from that other problem everything else seems to work okay so I don't understand why i'm being warned, how i'm duplicating mapping (one .xml.hbm per class and none for a subclass (as that mapping is in the baseclass .hbm)) and what potential consequences this "Duplicate Mapping" might have.

Please let me know if you have any data on this as it has me worried.

You are probably adding the same hbm.xml twice, maybe you are calling AddAssembly and then AddClass or something like that?

You're spot on. I was adding the assembly then adding the classes individually.

Thank you.
Simon Tamman.