Error: Call to a member function size() on null (and other issues!)

[TJB]

Hi all!

I set up a site on one hosting service, no problem. However, using exactly the same setup on a different hosting (specifically Fasthosts) and I've run in to a few issues (both subdomains) along the way. Although I've fixed the first few, more issues turn up, and feel I'm ultimately missing something. Here's the order of the issues:
1) One issue at install: 'Unable to determine if Apache mod_rewrite is installed...'. Based on other threads, I commented out 'Options +FollowSymLinks' (1.) to get past the 500 error and ultimately the install stage. Also commented out the 3 php_flags (6.).
2) All the fields were the same as the first site, so I used the Export/Import functionality to create the same fields on the second site. This seemed to go fine.
3) Issues again when adding images (repeater fields in this case). Got the 'Unable to move file to...' error message. Followed what prestoav did in this thread to resolve the issue:

 - by setting a new temporary uploads folder.
4) Images now upload, but the previously failed uploads show (despite the previous error) but cannot be deleted.
5) Next up, the image sizing functionality doesn't work - Error: Call to a member function size() on null. Also had issues with finding variables I'm using, despite the exact same setup working on the first site.

Ultimately I feel like I'm missing something here - clearly something is wrong and I can't figure out what to do. From reading other threads I get the feeling I perhaps should be reinstalling a fresh copy of processwire again, but I started with a fresh copy so don't understand why this would help. What should I be checking? As these are subdomains I added the path to the RewriteBase (11.) in .htaccess - not sure if this is actually doing anything.

Any guidance would be greatly appreciated! Many thanks.

Tim

[LostKobrakai]

Issue 1/2/3(/6) are all settings processwire doesn't have control over, as they are dependent on the webserver setup of your specific hoster. Issues 4/5 are probably follow up issues of your issue no 3. If your image/file uploads aren't working correctly it's easy to get in a state, where your assets/files folder and your database are out of sync, which can cause all kinds of errors if your code didn't account for these kinds of edge cases or the system is simply not meant to be usable in that state. That's where a (correctly installed) fresh install does help. It ensures that you start from a clean (known to be working) state.

[TJB]

Hi LostKobrakai,

Thank you for your reply. I guess my confusion lies around the fact that the install is fresh up until the point of issue 3. Or is the act of importing fields and modules changing that? Should I just be replacing the /wire/ folder as per upgrade instructions?