Problem error.log

I already have the online store running and I've checked the server and I find most of these errors in the same file.
My site www.disfracesporinternet.es

[Thu May 01 13:00:04 2014] [warn] [client 66.249.78.102] mod_fcgid: stderr: PHP Notice: Undefined variable: step in /var/www/vhosts/disfracesporinternet.es/httpdocs/templates/gk_storebox/html/com_virtuemart/productdetails/default.php on line 380
[Thu May 01 13:00:04 2014] [warn] [client 66.249.78.102] mod_fcgid: stderr: PHP Notice: Undefined variable: alert in /var/www/vhosts/disfracesporinternet.es/httpdocs/templates/gk_storebox/html/com_virtuemart/productdetails/default.php on line 383
[Thu May 01 13:02:46 2014] [warn] [client 66.249.78.102] mod_fcgid: stderr: PHP Notice: Undefined variable: step in /var/www/vhosts/disfracesporinternet.es/httpdocs/templates/gk_storebox/html/com_virtuemart/productdetails/default.php on line 380
[Thu May 01 13:02:46 2014] [warn] [client 66.249.78.102] mod_fcgid: stderr: PHP Notice: Undefined variable: alert in /var/www/vhosts/disfracesporinternet.es/httpdocs/templates/gk_storebox/html/com_virtuemart/productdetails/default.php on line 383
[Thu May 01 13:03:04 2014] [error] [client 95.20.42.229] File does not exist: /var/www/vhosts/disfracesporinternet.es/httpdocs/8568-7424-thickbox

Hi

Those are just warnings, not errors. Please just rise the level of errors stored in log file and only the crucial cases will be stored there. There is nothing to worry about from the warnings mentioned.

Thanks Teitbite. But and this type of error can be?

ERROR:
[Thu May 01 15:59:02 2014] [error] [client 79.157.0.34] File does not exist: /var/www/vhosts/disfracesporinternet.es/httpdocs/tienda, referer: http://www.disfracesporinternet.es/tien ... jo-detalle

Clicking on the link the characters to the end url has some rare

http://www.disfracesporinternet.es/tien ... 2JTlChB7Hk

#.U2JTlChB7Hk ??

Any idea?

I've found the problem. I share it for everyone.
This final code is added by http://www.addthis.com/.
The solution is to add a script under de Addthis code:

<script type="text/javascript">// <![CDATA[
var addthis_config={data_track_clickback:false}
// ]]></script>

Hi

Yes that's right. While generating a code in addthis You can select if track urls or not, so than this extra stuff is not added to url. Thank You for shearing this.