My entries are opening a “p” tag

Looks like when I write an entry WP is including a (P) tag which wont closes.
As result of this, I can’t validate the code, and can’t wrap the text around the images correctly (the standard code for doing it doesen’t work well).
I think that tag is not needed over there. I wonder how or from where it’s included.
Anyone knows how can I fix this problem ?

Thanks a lot.