Q: locked and loaded
nicht in Bezug auf Waffen.
A person is locked and loaded. とはどういう意味ですか?
A: "locked and loaded" means "ready". If you tell somebody to "lock and load", you're saying "get ready". Example -

"I'm locked and loaded!" (I'm ready!)

"It's time to lock and load" (it's time to get ready)

The phrase comes from loading a gun with ammunition, so you hear it used in battle. It could also be used ironically, or to be funny in a regular conversation.
Q: nicht dürfen とはどういう意味ですか?
A: Ja, basically mustn't~muss nicht.
It's very British sounding though. In N. America we'd say shouldn't instead


Q: ,, Übertreib nicht." は 英語 (アメリカ) で何と言いますか?
A: Do not overdo it
Q: Er möchte nicht, dass sein Foto veröffentlicht wird. は 英語 (アメリカ) で何と言いますか?
A: He doesn't want his picture to be published
Q: nicht vom Pech verfolgt sein は 英語 (アメリカ) で何と言いますか?
A: Obviously the best way to say it depends a lot on the context, unfortunately, but these are some ways you could say it:

"To be lucky"
"To not be accident-prone"
"To have Lady Luck on your side" (or "Lady Luck is with you")
Q: hey nicht weiter schlafen! は 英語 (イギリス) で何と言いますか?
A: @lilaa: "don't go back to sleep"