I’m not positive on this, but you may be running into this issue: http://support.microsoft.com/?kbid=106211
I would suggest trying one of two things:
1. Use two separate PC’s to test the shares; one connects to the aaa111 share and the other to the bbb111 share.
2. Establish your connection to aaa111 first, log off or clear your connections with NET USE and then log back in and try the connection to bbb111.
In either case, try to just use just “administrator” without the host name of the PC as part of the credentials. Obviously, if your client machine is on a Domain, be sure to remove the Domain part of the credentials if the Domain name is pre-populated in the user field. You may have to experiment a bit. Good luck.