I won’t ask you why you are using such a bad plugin, that is another story :). I can tell you though that the issue was reported a couple times before, by email, and that there are at least 1000 active users of the free plugin. Anyway…
That issue usually happens after using the Lite plugin and then the full one (i don’t know any case when the error shows on lite plugin update, but may be possible). It is fixable from phpmyadmin. I will try to explain you how to fix that yourself.
Go to phpmyadmin and select your wordpress database on left menu.
When you see tables list (also on the left menu), click on wp_multipressContent
On the main screen click on Structure tab at the top. That will show you the list of fields in the table. As the error say, you have one missing field so you need to add it.
At the end of that Structure page you have something like this: Add 1 field(s) At End of Table At Beginning of Table After.
Just leave as it is (default selection should be add 1 field at end of table) and click button Go
A new page will open with some form.
Type “article_limit” (without quotes) in the field name (first field). Then make this settings: Type: INT, Length/Values: 11, Default: None.
Leave all other fields empty and then click Save button.
That is all.. As far as i know all other people been able to fix this themself.
