[Plugin: WP Columns] not working

CSS is intentionally omitted.
Evidently you need more CSS fu.

Try something like this:

/* Column Classes */
.column-clearfix {clear: both;}
.column-wrapper-2 .column {
	height:100%;
	float: left;
	margin: 0 1.5%;
	width: 47%;
	background: url(../img/division.gif) right repeat-y;
	}
.column-wrapper-2 .column-first {}
.column-wrapper-2 .column-last {
	background-image: none !important;
	}
.column-wrapper-2 .column-1 {}
.column-wrapper-3 .column {
	height:100%;
	float: left;
	margin: 0 1.5%;
	width: 29%;
	background: url(../img/division.gif) right repeat-y;
	}
.column-wrapper-3 .column-first {}
.column-wrapper-3 .column-last {
	background-image: none !important;
	}
.column-wrapper-3 .column-1 {}

Also try changing the plugin settings to use before and after marks (Normal content before … after … separator), and in the CSS example above you would need to change the CSS Column Class Prefix.