IMBb's tt's have 7 positions, even if the number is under 1,000,000. E.g., the correct link to 'The Shawshank Redemption' is:
This is currently the situation for all 6-position links or less on Subscene. Seems the database column that hold the number is now indeed a number type, whereas it used to be (and should be) a text type. Added a new title recently and it had a zero-padded url, but upon submitting it had been converted to an integer, killing the link.
Instead of changing the column type you might also use lpad or similar to make it seven positions when generating the link. Would guess text type is faster, but it'd take a bit more storage space.
Hmm ... and the 'less than' symbol isn't automatically escaped when using it in a post.