Object reference not found error

[sybaris]

Hi,

When I try to run this query

select top 10 W2.name  from webresource W2
where NOT EXISTS (
 select TOP 10 W.webresourceid
 from webresource W
 inner join solutioncomponent SC on SC.objectid=W.webresourceid
 where W.webresourceid=W2.webresourceid
)

I have the following error : Object reference not set to an instance of an object

Regards Sybaris PS : I use the version 9.0.1