Ah, now I understand the problem (duh)
Don't use double quotes around strings, use single quotes. This is the most bulletproof solution, since then it doesn't matter if QUOTED_IDENTIFIER is set to either OFF or ON. Remember, in Transact-SQL, always use single quotes, never double quotes.
If, somehow you can't avoid to use double quotes denoting strings, then you must ensure that for the connection QUOTED_IDENTIFIER is set to OFF. It's a bit more hassle this way, since each connection can override the serversetting - you have to enforce this everywhere in the clientcode making the connection...