You can land safely above maximum landing weight, although it might cause damage to the tires or in extreme cases to the landing gears. Overweight landings are performed frequently[1] in emergencies, especially when an emergency occurs on or right after take-off.

There may still have been other overriding reasons not to land at the closest airfield in this case. We just don't know enough yet.

[1] http://avherald.com/h?search_term=overweight+landing&opt=0&d...