Yes. What's going on here is that the #content block element, because it's floated, is exactly as wide as its content. Whereas non-floated blocks, by default, have a width of 100% of their parent.
So, in this case, something has altered the total width of the content of the #content block element to make it narrower. I'm not sure what it is although I haven't looked very hard.
So, either giving the floated element (#content) a suitable width (i.e. the same width as its parent) or stopping it from being a float will work. Both will do the job as long as they don't have any knock-on effects. Neither appears to in this case.
If it was my site, I think I'd play around a bit to see what had altered to make the content of #content narrower. Fixing that might be the best solution, if it's not too hard to find.