Query Builder Error

We have an ItemType A and two Relationships Ra and TGV_Ra. In this, we are trying to get the details of Part Items which are present in this Relationship Ra and populating those in the Relationship TGV_Ra. 
But we've been getting this error - 

<SOAP-ENV:Envelope xmlns:SOAP-ENV="">schemas.xmlsoap.org/.../" xmlns:i18n="">http://www.aras.com/I18N">
<faultactor />
<faultstring>Failed to arrange records by desc order
Failed to retrieve ItemType </faultstring>

Can someone help me with this?