One thing to check/rule out which is pretty easy, check the vehicle charging system. Most of the BMW engines use a Multiple Spark Discharge or multiple trigger of the spark plug for each firing cycle. If the charging system is low, the DME will disable this feature.
Most of the BMW charging systems operate between 13.8-14.2 Volts that I have seen. Unfortunately the stupid E70 does a VERY poor job, if at all, about notifying the driver that there is any sort of charging problem.
You should be able to bring up and display the Voltage in the cluster, but it is also wise to verify the charging Voltage at the battery terminals and the under hood jump start connections.
This explains the Hidden Menu -
http://www.scoopz.com/m5board/E60_Hi...structions.pdf