Captions are overflowing caption box and not centered

If you have an area for custom CSS, add this:

.wp-caption p.wp-caption-text {
width: 100%;
}

If not, you’ll need to adjust the CSS (but if you update the theme the problem will return:

.wp-caption p.wp-caption-text {
font-size: 11px;
line-height: 17px;
margin: 0;
padding: 0 4px 5px;
ADD THIS: width: 100%;
}

DJ, :

ADD THIS: width: 100% ? Please exlain

the width of the caption text seems to be ruled by this style:

.post p{
	color:#666;
	width:715px;
	margin-top:15px;
	}

leave that is it is.

to compensate for the width of the captions, try to add either the suggestion by @djdoublexl189 or this to style.css of your theme:
.wp-caption p.wp-caption-text { width: auto; }

Thanks so much for the help, guys! I followed DJ’s suggestion and it worked like a charm – thank you so much!
-k