ACE stands for angiotensin converting enzyme - I think how an ACE inhibitor works is that the AC enzyme makes the blood vessels tighter and the drug blocks that so the vessels relax. This type of drug is the first line choice for reducing BP. There are lots of others if it's not suitable.
There is info about ACE inhibitors and NSAIDs like ibuprofen here:
http://www.phlaunt.com/diabetes/14046942.php
The biggest risk seems to be if you take both of these with a diuretic (water pill, like furosemide).
I take paracetamol daily for chronic pain... it's not ideal but I think it's the safest option. I have regular liver and kidney tests to make sure damage isn't being done.
The bottom line is if you are concerned about any drugs discuss them with your doctor. Better to be safe than sorry.