blank pages with some categories and when in cart

[bobmeetin]

My zencart install is running 1.5.1.

I have a site that has been running smoothly for some time. No issues, pages load fast enough and the checkout system works great. The site is hosted on a VPS server and shares spaces with several other sites. None are notorious bandwith hogs, again no problems. Some are Joomla, some Magento, some simple HTML.

About 2 weeks ago the time arrived to upgrade PHP from 5.2 to 5.3 as 5.3 is now required for the latest Joomla. This seemed to be fine. Now I am seeing some weird things with the shop rendering it unusable. Visiting specific categories will render a "blank" page, this one being an example:

http://192.254.209.56/~dgodod/index....th=113_114_116

Moving along, if you find a product and add it to the cart, all pages in the cart are blank. So, click to add any item to the cart and you get the blank page. If you return to the home page then click on the "shopping cart" button you also draw blanks.

I don't remember changing anything around that time period that would have led to the problem and the only major thing has been the PHP upgrade. The other day I asked the s/a staff to reinstall 5.2 but leave 5.3 as the default. To force it to read 5.2 I add the following line into the .htaccess:

AddType application/x-httpd-php52 .php

Of course this made no difference. I have access to make the account read a custom php.ini if necessary. Ideas?

[DrByte]

http://www.zen-cart.com/content.php?124-blank-page

[bobmeetin]

I think I have this fixed but I don't see why it occurred in the first place. The site was up, running smoothly for several months, before I discovered the problem quite by accident.

As the other thread suggested I took a look in ~/www/logs and found a slew of error files, the contents like:

[25-Aug-2013 00:42:46] PHP Warning: Cannot modify header information - headers
already sent by (output started at /home/$account/public_html/includes/languages/e
nglish/extra_definitions/theme684/internet_reviews_defines.php:5) in /home/$account/public_html/includes/functions/functions_general.php on line 45

I had not made any recent changes that I knew of with the sidebox but I went into zencart admin / Layout Boxes Controller and found a .swp version of internet reviews, also this and some other boxes were highlighted in bold red. The reviews box was not something I was using so I deleted all the relevant files normal and .swp) from the filesystem. To remove it from the Layout Boxes Controller I removed the entry from the database table:

mysql> delete from layout_boxes where layout_id = 129;

I went back to the public website and checked, and the problem still existed and was pointing to one of the other highlighted boxes in Layout Boxes Controller. I repeated the process, checked again, still broken and the latest log error was pointing to:

[02-Sep-2013 00:11:51] PHP Warning: Cannot modify header information - headers already sent by (out
put started at /home/$account/public_html/includes/languages/english/extra_definitions/theme684/social
_media_sidebox_defines.php:5) in /home/$account/public_html/includes/functions/functions_general.php o
n line 45

Repeating the process a third time resolved the logs/errors and the problems on the public frontend. So, no I do not know when or how this got started, but it is now working.