I just fixed it.

That was a small bug introduced during the redisign of Odoo Apps.

Download link seems to be broken somehow, but you can still get that module from launchpad with bazaar.

bzr clone lp:~bhc-team/bhc/7.0

mmh.. seems to be at all apps.. other apps doesn't work, too

example

https://www.odoo.com/apps/7.0/account_parallel_currency

links are broken...

Download from https://www.odoo.com/apps/7.0/product_variant_multi_advanced/

is broken also.  Can not install from inside OpenERP and the direct download takes you to the endless loop of the Signup process.