If your sole income is from benefits, then you won't be able to do an IVA. You could consider a debt management programme though.
Sharing from experiences of dealing with debt
The greatness of a man is not in how much wealth he acquires, but in his integrity and his ability to affect those around him positively.
Bob Marley. http://kallis3.blogs.iva.co.uk
Your DLA and incapacity benefit is paid to you to look after yourself - not to deal with debt repayments. I would also consider bankruptcy proceedings - which may well be the better option if you have no assets of material value.