There is an ongoing outage on the primary CPAN mirror. It is possible to work around the issue by using MetaCPAN as a mirror.

ChangeLog for Apache::GD::Thumbnail

0.01 - Jan 21, 2002 - Started
0.02 - JAn 22, 2002 - Removed some debug code that shouldn't have been there
0.03 - Mar  1, 2002 - Send cache control response BEFORE generating the thumbnail...