There are sevrral things you can do:
You can delete the folder and skins from your server (just the one you created, not the whole skins folder) - dnn will kick out an error when you try to go to your site, but it will revert to the default skin and you will be able to go to your setup tab and apply one of the supplied DNN skins.
you can edit the .ascx skin files directly. When you upload or parse an HTML skin, DNN creates a n ascx file with the same name. When you view a page, it is actually the ascx file that DNN uses, not the HTML file.
Find the ascx file and look for yur contant pane.
Edit it so that it looks something like this.
<div id="contentpane" runat="server"></div>
or
<td id="contentpane" runat="server"></td>
Save it back to yur site (FTP or whatever you have to do)
and go to your site. - you should have a contentpane.
OR.
You can copy one of the standard DNN skin files(the ascx file) to the folder where the skin you developed lives,
and rename it so that it matches as the skin you developed.
Advice: when working on new skins: do not apply them to the portal until you are sure that they work.
create a new tab and apply the skin to just that tab. If you get stuck, you can use the pages tap (under admin) to change the skin
or you can just delete the skin package let DNN revert to the default skin.
BTW: Your problem earlier with the tokens [CONTENTPANE:1] and [CONTENTPANE:2] etc. probably occurred occurred because you did also not have a token called [CONTENTPANE],
without the enumerator