This used to be a frequently reported problem - sidebar at bottom of page. The most likely cause of this problem is there may be something in a blog post which is too wide for the main column. It could be an image, a video, a table, an unbroken line, etc. The culprit may also be in the sidebar. Below are the troubleshooting tips for such problems:

Step 1: Determine width of main column, sidebar

Step 2: View individual post pages one by one. This can be done in various ways. Refer to  Troubleshoot sidebar at bottom of page problem part 3. The post where the sidebar is at the bottom of the page is the culprit.

Step 3: When you have isolated which blog post is causing the problem. 

Step 4: Proceed to edit the post to remove the problem. For example, if it is a YouTube video, refer to Resize Youtube video to fit main column, sidebar

Step 4a: Resize Google Video to fit main column, sidebar. Resize Live Video to fit main column, sidebar. Resize eSnip Music Player to fit sidebar 

These examples should give you an idea of how to resize anything to fit anything.

Step 5: When done, republish post

Step 6: If you cannot find the culprit using the above steps, then check everything in the sidebar.

Step 7: If you can find nothing wrong, check the template. Refer to Troubleshoot sidebar at bottom of page Part 1 or Troubleshoot sidebar at bottom of page Part 2.

Step 8: If you don't want the hassle of checking the template, backup your template

Step 9: Backup all Page Elements that can be backed up.

Step 10: Change template

Best of luck to you. Hope your problem is solved

Peter Chen @ Enviroman (Blog*Star)

Blogger Tips and Tricks

Dummies Guide to Blogger

Blogger FAQ

Beginners' Guide to Blogger