What about "Burada ağlayabilmesın"?
Definitely not good :) When you negate -(y)Abilmek, you simply use the suffix -(y)A with the aorist endings. The "bilmek" part of the verb isn't used in the negative.
Thanks a lot
Can I say: ağlamayabilirsin?
no, that just tells us that there is possibility; so it is "you might not cry" in English, while "cannot" indicated that it is impossible / not allowed