Can anyone help me I rooted my Android 2.2 and then I used the root explorer and accidentally deleted the wifi folder in the root explorer now I can't get access to wifi they keep showing *error*

Re-install the root files. I doubt you can pull the specific files required just for the wifi drivers.

How do I re-install it?

Didn't you root your phone originally? Do the same steps to re-flash the ROM.

I am a noob sorry to ask a lot of question. How do I reflash can you please show me the steps :/

How did you root your phone originally? You say you did in your first post.

I rooted using universal androot 1.6.2beta and used superuser

Just you have to delete wifi folder in the root explorer now you will access to WiFi.