you mean Rich Text Editor ?
you have a button to create a table, no ?
more precision of your problem...
Yes, i mean Rich Text Editor. I figured out what the problem was. I had to add the use of table plugin to tinyMCE.init function at create.jsp and edit.jsp files, in order to make the table functionality available.
If you want to add a plugin, just go to TinyMCE webpage and find the documentation of each plugin. There, you can find instrunctions how to do it. It's very simple.