Error while updating lookup table through PSI

Hi,

I am trying to update a lookuptable through PSI using following code : 

$lookupTableGuid = $svcPSProxy.ReadLookupTables($EPMTYString, 0 , 1033).LookupTables  | where {$_.LT_NAME -eq $Lookuptablename}
$lookuptable = $svcPSProxy.ReadLookupTablesbyUids($lookupTableGuid.LT_UID, 1 , 1033)
$lookuptablerowValues = $svcPSProxy.ReadLookupTablesbyUids($lookupTableGuid.LT_UID, 0 , 1033).LookupTableTrees 

 
#get lookup table count 
$lookuptableValues = $svcPSProxy.ReadLookupTablesbyUids($lookupTableGuid.LT_UID, 0 , 1033).LookupTableTrees 
$count = $lookuptableValues.Count +1 
#Insert the rows of table in Lookup Table 
foreach ($rows in $table)
{
        $value_Code  = $rows.Item("Project_code") 
        $value_Name  = $rows.Item("project_desc") 
        $GUID = [System.Guid]::NewGuid()
        $LookupRow = $lookuptable.LookupTableTrees.NewLookupTableTreesRow() 
        $LookupRow.LT_STRUCT_UID = $GUID 
        $LookupRow.LT_UID = $lookupTableGuid.LT_UID 
        $LookupRow.LT_VALUE_TEXT = $value_Code
        $LookupRow.LT_VALUE_DESC = $value_Name
        $LookupRow.LT_VALUE_SORT_INDEX =  ($count ++) 
        $lookuptable.LookupTableTrees.AddLookupTableTreesRow($LookupRow) 
 }

$error.clear() 


#Exceptions Handling :
Try 
    { 
       $svcPSProxy.UpdateLookupTables($lookuptable , 0 , 1 , 1033) 
    } 
Catch  
    { 
        write-host "Error updating the Lookup table, see the error below:" -ForeGroundColor Red -BackGroundColor White 
        write-host "$error" -ForeGroundColor Red 
    } 

Initially, I tried to run with value of $value_code as "AACL", the code worked.

But when I tried to insert value of code as "AACL - ALKYL AMINES CHEMICALS LIMITED"

I got following error:

Exception calling "UpdateLookupTables" with "4" argument(s): "Response is not well-formed XML."

I could not understand why this error is appearing as I just added ' - ' to my code value. I checked for validity of ' -  'in the targeted column. No issue with that.

Please help.

Thanks and regards,

Jayesh