Wc3 validation errors in theme code

I am using twenty eleven theme, WP 3.3.1, and WP-eCommerce plug in on my site: http://www.greenhillsoaps.com

When I run the pages through the Wc3 Validator, I get error codes and warnings. For Example line 134 of the code on my home page has the following line of code:

…one” href=”http://greenhillsoaps.com/”></g:plusone></div><li class=”share…

I get a warning:
Element name g:plusone cannot be represented as XML 1.0.

and I get an error:
Element g:plusone not allowed as child of element div in this context. (Suppressing further errors from this subtree.)

Further, on the same line (134) there is another line of code:

…Us: ” style=”width:97px; height:20px;”></iframe></div><li class=”share-en…

generating the following 3 error messages:

The allowtransparency attribute on the iframe element is obsolete. Use CSS instead.

The frameborder attribute on the iframe element is obsolete. Use CSS instead.

The scrolling attribute on the iframe element is obsolete. Use CSS instead.

Line 152 has the following code:

… Personal Publishing Platform” rel=”generator”>Proudly powered by WordPress

with the error:

Bad value generator for attribute rel on element a: Keyword generator is not registered.

Lastly, line 167 has the following code:

<script type=”text/javascript” charset=”utf-8″>

And the associated error message:

Element script must not have attribute charset unless attribute src is also specified.

I am new at word press and the world of CSS, HTMS, XML, PHP…..
This code was provided by the Theme parent. I am making all changes in a Child theme.

Can someone please advise me what I should do about these errors. I am sure it is something very simple that my aged mind cannot quite get to.

Happy New Year!