First, it would help to know which version of Corel you are using. Second, which OS? Third, what kind of feathering are you talking about? There is a simple method for feathering but do you mean ragged edges, paintbrush like strokes, etc.? How are you trying to add a gradient background?

Give us some details. I've used Corel on W98se and W2K and have done both of the things you mention without crashing.