exchange installation problem

Error:
The DNS domain name is invalid. It contains characters other than 'A'-'Z', 'a'-'z', '0'-'9', '.' and '-'.
For more information, visit: http://technet.microsoft.com/library(EXCHG.150)/ms.exch.setupreadiness.ServerNameNotValid.aspx

Warning:
Installing Exchange Server on a domain controller will elevate the permissions for Exchange Trusted Subsystem to domain administrators.
For more information, visit: http://technet.microsoft.com/library(EXCHG.150)/ms.exch.setupreadiness.WarningInstallExchangeRolesOnDomainController.aspx

Warning:
Setup will prepare the organization for Exchange 2013 by using 'Setup /PrepareAD'. No Exchange 2010 server roles have been detected in this topology. After this operation, you will not be able to install any Exchange 2010 servers.
For more information, visit: http://technet.microsoft.com/library(EXCHG.150)/ms.exch.setupreadiness.NoE14ServerWarning.aspx