Hi, Thanks peredur for your prompt and well-researched reply!
Some of these errors concern the files that came with the WordPress Theme itself -- that also came from the Net as unsupported open source.
Apparently, with my beginner's expertise in Java & PHP I shouldn't be playing around with the aforesaid codes.
Only a few errors pertained to what I had deliberately added to my Posts, e.g. the <p> tags -- that were successfully experimented to create double-space between paragraphs (this Theme gives only single space, deapite trying 3 carriage-returns). As per your advice, I have now removed these tags.
However, the white space to the right of the webpage persists in IE8 --although it is not there when I open the same webpage in Google Chrome, Opera, Mozilla or Safari. Kindly advise, asap. Thanks in advance!