这两句都是错的.
第二句need作情态动词,后面直接加not,情态动词后面接的是动词原形,如：
You needn't tell George.
You needn't record the program on the tape.
第一句中need作实义动词,后接的是动词不定式,应该说：
I just don't need to talk to anyone for a while.
另外,动词不定式的否定式,not或never要加在不定式的记号（小品词）to之前,不能加在to与动词原形的中间,否则不符合语法（虽然外国人现在也常这么说）.如：
Try not to worry.
He wished never to see him again.
Let's not go.
It seems not to be right.
希望我能帮助你解疑释惑.