Theme development

Hello there,

I was following a Drupal theme tutorial, ran into bad problems (white screen of death). I was able to get it to show something on my home page. I changed the default theme to Bartik in the settings.php file.

Now, the admin toolbar shows on top, but if I try going into appearance, configuration, or anything else, the white screen pops up again. I don't know what to do. Any help would be appreciated!

I also get these listed errors on the hope page (they show up multiple times on the page, I just truncated it since it repeated itself:

Hello there,

I am fairly new to drupal, and I was following a tutorial on customizing themes. I have my remote server conntected, and I am able to add/change/delete files, but nothing seems to be working. I am still getting the WSOD.

I have tried replacing my enabled theme to an already working theme such as Bartik or Garland. I have tried changing my settings.php, but that doesn't seem to work. I have tried using drush, but get error issues:

Hi,
we are developing a from-scratch theme in D7.
The designer has included the tag <meta content="width=device-width, initial-scale=1" name="viewport"> in the head section, and I placed this in the html.tpl.php file in our theme directory and cleared caches.

however, we are also using the HTML5 Tools module, and the theme debug output shows:

Hi all,

It seems that I'm struggeling with understanding the PHP caching :-)

Here's another example of my code where the drupal caching is 'bullying' me:

I installed (via wget and tar) the devel module for D7 and I put it in /sites/dev.foo.com/modules so that it wouldn't get copied to the production site.

However, it isn't showing up in admin->modules. Since I haven't used a site-specific modules directory before, have I created it correctly? It is owned by the apache user like all other files.

I have searched without luck for a D7 dev module which can help identify which template file is the source of each section of html output (I would imagine that it would do this by inserting comments such as
<!-- begin sites/all/themes/foo/bar.php.tpl --> and
<!-- end sites/all/themes/foo/bar.php.tpl -->

Is there such a beastie? Or some other means of determining what needs to be overridden?