Hi Azneita,
Mitali has given some explanation on the same but even I do not think that the delay is because of student Visa backlog, since the student visa season should be over by now, also the student visa is mainly handled by the local high commissions at the home country.
As per the CIC website it says as below :-
Skilled Worker applications received after November 28, 2008 (Federal)
July 1, 2009 to June 30, 2010
NOTE: Processing times for Federal Skilled Worker applications received on or after June 26, 2010, are not yet available. For applications sent before June 26, 2010, the Centralized Intake Office in Sydney, Nova Scotia, is currently working on applications received up to June 25, 2010.
regards,
Sunnysport