I can only read the first 5 pages of my epub

I recently purchased an ebook with DRM to read it in my Kobo e-reader, so I downloaded ADE 4.5 but it crashed after page 5.  Following instructions on Kobo forums I uninstalled ADE 4.5 and downloaded ADE 3.0.  It keeps crashing after page 5, both on my ereader and also in the computer using ADE 3.0.  So now I cannot read my ebook at all.  Any suggestions? Thanks.