Fix mozilla components loading when sugar is running from source.

We don't attempt to load components from source, since that would
be insanely complicated.

1 files changed, 1 insertions, 1 deletions

diff --git a/sugar/env.py b/sugar/env.py
index 4bee509..03cfea7 100644
--- a/sugar/env.py
+++ b/sugar/env.py
@@ -22,7 +22,7 @@ def _get_prefix_path(base, path=None):
     if os.environ.has_key('SUGAR_PREFIX'):
         prefix = os.environ['SUGAR_PREFIX']
     else:
-        prefix = '/usr'
+        raise RuntimeError("The SUGAR_PREFIX environment variable is not set.")
 
     if path:
         return os.path.join(prefix, base, path)