You can get this error on some INSERT statement in the databse with triggers. It's a bug in some versions of the Qt library toolkit. It should be fixed in the Qt 4.2.3 and later.
Query Error: unrecognized token: ":"
SQL statement not found. Pos: 51. Start: 25. End: 44.
You can get this error when you want to run a statement in the sql editor with an unexpected text wrapping.
Collect your editor content and fill the bug report, please.
Then use a workaround: select your statement by keyboard or mouse.