What does the exclamation symbol mean?

[papagato]

I download pages and keep get cut off or the connection stalls. Also, sometimes I get a caution symbol (yellow sign with exclamation mark) next to some files, what does it mean?

[stanbusk]

Those exclamation marks are warnings. You will see them on redirected pages or pages not found for example. Try to use very last version available here as it handles warnings much better.