QuickLinks -- Click here to rapidly navigate through this document

Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

        We hereby consent to the incorporation by reference in the Registration Statements on Form S-8 (Nos. 333-31022, 333-40267, 333-43537, 333-43539, 333-43541, 333-43543, 333-43635, 333-67487, 333-92735, 333-100553 and 333-141038), and on Form S-3 (Nos. 333-121088, 333-31268, 333-85279, 333-88097, 333-95841 and 333-154309) of our reports dated June 11, 2008 relating to the consolidated financial statements and financial statement schedule for the two years ended April 30, 2008 which appear in this Form 10-K/A.

/s/ Vitale, Caturano, and Company, Ltd.
Boston, MA
February 12, 2009

QuickLinks

Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM