Re: show sidebar on single post pages?
explained in last comment.
Look at that code, specifically look at the classes and the id’s on various elements such as the sidebar where the value needs to be quoted it needs to be plain quote marks as your keyboard will enter. At the moment the quote marks are not correct character entities they are angled .
Check the code you posted to pastebin, I have edited the first quote mark of the class on the element ‘content’ to show you a visual comparison of the two different marks – compare to the sidebar element at bottom of page:
I don’t claim this is definitely going to cure the issue but it is a problem for correctly behaving browsers and needs to be put right before moving on to look at other possible causes – if the isue still persists