Error while reading ID of own business system from the SLD for system QTP and client 100 Error when communicating with the Landscape Directory

Dear Exp,

I have one interface SOAP -> PI -> PI. Interface was running normally till last week, today when i was doing some testing for this interface I am getting error "Error while reading ID of own business system from the SLD for system QTP cleint 100 when communicating with Landscape Directroy"

And.

1. I have not done any changes in the interface

2. I cleared all casche abap, java and sld... but still no luck

3. I am using business component not business system

4. I have checked SLDPICUST and it looks good in pi system

I have referred some threads in sdn and followed the same but not norking yet.

Your suggetions will be helpful to clear the issue...