Not that this has anything to do with the error you are receiving, but I think you need to start by getting your code correct(as I noted earlier in this thread). The way you are using the UDF is not right. There is a FAQ on using and creating UDFs: http://www.kixtart.org/forums/ubbthreads.php?ubb=showflat&Number=82017&page=1#Post82017

Please consider the following changes: (I could not test this so its very possible there are bugs)

break ON
$=setoption("Explicit","on")
$=setoption("NoVarsinstrings","on")
dim $test1, $server, $store
 

$test1="aber.nade" ; The period in this account name causes the IDispatch error 
 

$Server=HOMEMDB($test1,"Server")
$Store=HOMEMDB($test1,"Store")
? $store
? $server
 

Function HOMEMDB($ADAccountName,$mode)
  Dim $AdoCon
  dim $AdoCommand
  dim $Recordset
  dim $Filter
  dim $homemdb
  dim $store
  if len($ADAccountName)>0 
      $filter=" where samAccountName='"+$ADAccountName+"' "
      $AdoCon = CreateObject("ADODB.Connection")
      $AdoCon.Provider = "ADsDSOObject"
      ; Current credentials are used, as username and password aren't specified 
      $AdoCon.Open("Active Directory Provider")
      ; Create ADO command object for the connection. 
      $AdoCommand = CreateObject("ADODB.Command")
      $AdoCommand.ActiveConnection = $AdoCon
      $AdoCommand.CommandText ="Select homemdb from 'LDAP://"+GetObject("LDAP://rootDSE").Get("defaultNamingContext")+"' "+$filter
      ; Execute the query. 
      $Recordset = $AdoCommand.Execute
      $homeMDB=split($recordset.fields("homemdb"),",")  ; This gives the error 
      select
        case $mode="Store"
          $store=split($homemdb[0],"=")
          $HOMEMDB=$store[1]
        case $mode="Server" 
          $HOMEMDB=right($homemdb[3],4)
      endselect
  endif
Endfunction


Please read the faq and look through/test my example. If you don't understand why I did it this way then please ask.

If we can get this correct, we might be able to figure out the other problem as well.