Hi in SRM 70 a new workflow technology is introduced and by defualt this new workflow is to be active,
please chekc what kind of workflow you are using.
you may choose to use the old(SRM 50 like) workflow too and this should then bring back to old fucntionality and not cause any effect.
check sap note 1276845
for more info.
were all the steps followed for process controled workflow?
please chekc again based on the documentatin for each step in the IMG.
also if you going to use only zero step automatic approval , why are u going for process controlled workflow, you could simply
retain your old workflow settings by chooing application controlled workflow instead of process controlled workflow.
The process contolled workflow is more useful when you have complex approval rules.