I experienced this very sort of thing on my first attempt to purchase BTC with USD, but in BTC-e.  Several times edited the rule (while disabled) after the first failure and re-enabled.  This resulted again in a beep-notify, rule status claimed done, no order opened, no transaction completed.

Amount was around $10, rule was for spend all @ Buy Price, triggered at Sell Price being lower than specified.  Had to log into BTC-e and place order manually.