Recently i m have the problem of uploading  the new template for the blog.This make me so 'crazy" because the 3th party theme template cannot be use..the problem is like this...after upload the template..when we try to preview or save template will appear error mesage.Usually this error message start will letter BX-XXXXX & XXXX is another number or letter.Then i'm start looking for solution at internet..After doing research for almost 1 day(so limited solution for this problem) this is the solution for the problem.I'm going to make teh simple as i can for the way solving this.Got question give your comment ok.

1.Clear your web browser cache & cookie.

2.Change the widget ic at tempalte source code.The step is like this

1. Open your source code using wordpad or other suitabele aplication
   
2. Press"ctrl+f" for use the find box function
   
3. Type "widget id" in find-box
   
4. You will find widget id:feedX(where x is number)
   
5. Change the x into another number
   
6. repeat for another widget
   

3.Delete widget manualy at page elemnent but make sure to save backup before do that
4.Use alternative web broser
5.If still cant just try to use another PC and keep searching internet for solution.