As the freighter approaches Earth after coming out of the Time Warp, the continents look very much like they do in the Present Day. 65 million years ago, Korea and Japan would not have been in the positions that they are seen in.
The goof items below may give away important plot points.
Crew or equipment visible
When the Doctor shoves Adric's gold badge into the Cyberleader's chest, a silver box can be seen pressing against David Banks's face. Additionally, a wire attached to a small microphone is revealed and can clearly be seen when the Cyberleader explodes.
Just before and when the freighter crashes into Earth, the TARDIS
monitor shows the freighter suspended in space and not moving when it blows up. Also, Earth is nowhere to be seen on the monitor. This has been corrected by CGI on the dvd.