Many varieties of peppers normally develop dark - almost black nodes and stem joints. It is normal.

As to the blooms falling off - it is a weather-related (most likely cause) condition called 'Blossom Drop' and I linked the FAQ on it below. It discusses the causes in detail.

Using that term you can also learn a great deal about it on the web and there are lots of discussions here too that you might want to browse through.

Dave

Here is a link that might be useful: Blossom Drop FAQ

Feeding plants with Phosphate rich fertilizer will help.Water regularly.