First of all I upgraded my Aspect HD to Prospect HD.

I'm working on a project where the files are partly captured with Aspect and the other half of it is captured with prospect.
When I start editting on my premiere timeline, with the aspect captured files,
my timeline turns black within a few minutes.

Is it a problem to edit aspect captured files on a Prospect installed premiere?

If not, is it possible to use aspect captured files with prospect captured files on the same timeline?

If the above things should not be a problem then I know I have to search for my problem elsewhere.

There are no limitations mixing Aspect and Prospect source data within a single project.