[Voyage-linux] remounting issues and screen issues

[bagheera]

Hi, i have problem with remounting file system, sudo remountrw works fine,  
but after typing sudo remountro i got this:

mount: / is busy

I have also problem using screen, it doesn't launch:

Cannot make directory '/var/run/screen': Access denied

Each time i have to make that dir manually and set its permissions to 777,  
and then i can (finally..) use screen for my wget downloads (it writes  
data on mounted flashdrive)

What i supposed to do to have screen working with main file system mounted  
read-only?