Exchange 2007 - OWA - Multiple Domains in 1 Forest

Weird problem and I know it is more then likely permission based, but I cannot figure it out. So here it is.
I have Exchange 2007 running with multiple CAS servers and Clustered Mailbox servers. I am hosting it in a Root - Child forest topology. When trying to access e-mail via OWA for users that within one of the child domains I get the following error: Read below the error message for more details.

Request
Url: https://xxx.xxx.xxx.xxx:443/owa/lang.owa
User host address: xxx.xxx.xxx.xxx

Exception
Exception type: Microsoft.Exchange.Data.Storage.StoragePermanentException
Exception message: There was a problem accessing Active Directory.

Call stack

Microsoft.Exchange.Data.Storage.ExchangePrincipal.Save()
Microsoft.Exchange.Clients.Owa.Core.RequestDispatcher.DispatchLanguagePostLocally(OwaContext owaContext, OwaIdentity logonIdentity, CultureInfo culture, String timeZoneKeyName, Boolean isOptimized)
Microsoft.Exchange.Clients.Owa.Core.RequestDispatcher.DispatchLanguagePostRequest(OwaContext owaContext)
Microsoft.Exchange.Clients.Owa.Core.RequestDispatcher.PrepareRequestWithoutSession(OwaContext owaContext, UserContextCookie userContextCookie)
Microsoft.Exchange.Clients.Owa.Core.RequestDispatcher.InternalDispatchRequest(OwaContext owaContext)
Microsoft.Exchange.Clients.Owa.Core.RequestDispatcher.DispatchRequest(OwaContext owaContext)
System.Web.HttpApplication.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

Inner Exception
Exception type: Microsoft.Exchange.Data.Directory.ADOperationException
Exception message: Active Directory operation failed on domain controller name goes here. This error is not retriable. Additional information: Insufficient access rights to perform the operation. Active directory response: 00002098: SecErr: DSID-03150A45, problem 4003 (INSUFF_ACCESS_RIGHTS), data 0

Call stack

Microsoft.Exchange.Data.Directory.ADSession.AnalyzeDirectoryError(PooledLdapConnection connection, DirectoryRequest request, DirectoryException de, Int32& retries, Int32 maxRetries)
Microsoft.Exchange.Data.Directory.ADSession.ExecuteModificationRequest(ADRawEntry entry, DirectoryRequest request, ADObjectId originalId)
Microsoft.Exchange.Data.Directory.ADSession.Save(ADObject instanceToSave, IEnumerable`1 properties)
Microsoft.Exchange.Data.Storage.ExchangePrincipal.Save()

Inner Exception
Exception type: System.DirectoryServices.Protocols.DirectoryOperationException
Exception message: The user has insufficient access rights.

Call stack

System.DirectoryServices.Protocols.LdapConnection.ConstructResponse(Int32 messageId, LdapOperation operation, ResultAll resultType, TimeSpan requestTimeOut, Boolean exceptionOnTimeOut)
System.DirectoryServices.Protocols.LdapConnection.SendRequest(DirectoryRequest request, TimeSpan requestTimeout)
Microsoft.Exchange.Data.Directory.PooledLdapConnection.SendRequest(DirectoryRequest request, LdapOperation ldapOperation)
Microsoft.Exchange.Data.Directory.ADSession.ExecuteModificationRequest(ADRawEntry entry, DirectoryRequest request, ADObjectId originalId)

-------------------
This is only when the user is in one of the Child Domains, if the user is in the Root Domain then they can access OWA just fine.

Setup ---- Root Domain = a.local       Child1 Domain = b.a.local        Child2 Domain = c.a.local
Users in a.local can access OWA just fine, users in b.a.local or c.a.local cannot access OWA. They can get past the login screen, but when it ask for the Time Zone and etc. page on OWA it fails once you press ok.
I am trying to get this deployed ASAP, would someone please help !!!