Not every space flight failure is the result of an explosion.
The Progress vehicle did actually enter an orbit (it reached space and was circling the Earth for a couple days), just the wrong one and after that it spun out of control and was no longer controllable from the ground. Since there is still some atmosphere and some drag in low Earth orbit it eventually was slowed down enough to burn up.
Basically, it failed because it couldn't be controlled anymore, no explosions involved. (Had it been launched to an higher orbit it may well have stayed up for a long, long time, no explosions or anything else interesting going on, just spinning round and round and being uncontrollable.)
