how to unblock proaction bagless upright?

i have a proaction bagless upright model VC9230S-4 my builders have used it and it is belching out dust i think they have bunged it up. Itworks fine with the hose and accessories, the book of words says to 'UNBLOCK IT' but gives noinstructions on howto do this. HELP.
sally spruels, August 2009


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