Creation of trust fails: cannot continue

I have two different forest with 2 different domains . 1st one called mango.net and 2nd called cherry.net,there is no shared root DNS server and the root DNS servers for each forest DNS namespace are running Windows Server 2008 R2 so i configured DNS conditional forwarders in each DNS namespace to route queries for names in the other namespace. 

As you can see our DNS and Netbios names are not the same and I have verified that both domains have the different SIDs too (I have verified it by using the tool PSGetSID). 

I am trying to create trusts between 2 domains. At the end of the Trust wizard, I received the following error in the New Trust Wizard:

The operation failed. The error is: cannot create a file when that file already exists.

I can Ping between the servers in different domains.
Both forest and domain functional level are windows 2008 R2
Nothing appears under the event log 

Anyone have any ideas about that. Please let me know.