I don't want to put words in the Speaker's mouth. I do not know specifically what the Speaker had in mind, but I believe that, according to his interpretation of the situation, the government had decided not to provide the documents to the House of Commons. As a reasonable man, he believes that an explanation should be given as to the reason why documents are not being provided to Parliament. However, he received no explanation, prompting him to state that the committee should look more deeply into the issue in order to ascertain why no explanation was provided to Parliament regarding the information requested by the committee.
On March 16th, 2011. See this statement in context.