Thomas Mellman gets a visual bell if he types any multi-key map very fast!
Check if timeoutlen and ttimeoutlen have reasonable values (not negative and not so large that the most significant bit is set). Also, what happens if you go into inset mode and type (some garbage) very fast? Does vim accept each and every key typed? (Aside: for the specific map you use to search for the word under the cursor, see :help * and :help #.) --Suresh
