I've been stuck on a file upload issue for nearly a week and I'm no closer to resolving the problem.

Basically, I am working on a file upload script and the issue is relating to the upload of files. Specifically it tends to be with files 10MB+

I thought this issue would be resolved promptly as it seems obvious that it is the INI file rejecting files over 10MB. This isn't the case though as occasionally a 15MB test PDF file gets through and uploads correctly.

So what have I done to try and resolve the issue?

1. I went through the config file and made sure that I had the correct attributes set which are:
max_execution_time 300
max_file_uploads 20
max_input_time 600
memory_limit 128M
post_max_size 70M
upload_max_filesize 50M
upload_tmp_dir C:\Windows\Temp\
2. This had no effect, so knowing it's a 500 internal server error, I checked the error log. There was nothing in the PHP error log, so in the INI file, I added a custom error log and still no PHP error. After more searching, I discovered another log in ISS W3SVC26 and this is what it contains relating to what I believe is the upload:
#Software: Microsoft Internet Information Services 7.5
#Version: 1.0
#Date: 2013-05-09 12:29:21
#Fields: date time s-sitename s-computername s-ip cs-method cs-uri-stem cs-uri-query s-port cs-username c-ip cs-version cs(User-Agent) cs(Cookie) cs(Referer) cs-host sc-status sc-substatus sc-win32-status sc-bytes cs-bytes time-taken

2013-05-23 13:32:17 W3SVC12 DSVR017177 213.171.205.235 POST /account/test/server/php/ file=GibLive2611.pdf&_method=DELETE 80 - 88.202.236.161 HTTP/1.1 Mozilla/5.0+(Windows+NT+6.1;+WOW64)+AppleWebKit/537.31+(KHTML,+like+Gecko)+Chrome/26.0.1410.64+Safari/537.31 PHPSESSID=d828b568c8c122e45b4b376ff1287a74;+__atuvc=0%7C13%2C0%7C14%2C0%7C15%2C0%7C16%2C18%7C17;+__utma=11234787.1386610922.1366208206.1369298491.1369306266.65;+__utmc=11234787;+__utmz=11234787.1366208206.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none) http://www.free2read.co.uk/account/test/ www.free2read.co.uk 200 0 0 622 786 264
2013-05-23 13:32:17 W3SVC12 DSVR017177 213.171.205.235 POST /account/test/server/php/ file=GibLive2611%20%281%29.pdf&_method=DELETE 80 - 88.202.236.161 HTTP/1.1 Mozilla/5.0+(Windows+NT+6.1;+WOW64)+AppleWebKit/537.31+(KHTML,+like+Gecko)+Chrome/26.0.1410.64+Safari/537.31 PHPSESSID=d828b568c8c122e45b4b376ff1287a74;+__atuvc=0%7C13%2C0%7C14%2C0%7C15%2C0%7C16%2C18%7C17;+__utma=11234787.1386610922.1366208206.1369298491.1369306266.65;+__utmc=11234787;+__utmz=11234787.1366208206.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none) http://www.free2read.co.uk/account/test/ www.free2read.co.uk 200 0 0 622 796 244
There are many instances of the above, each time I try and upload a file. I have no idea where to start with the above, I couldn't find out much from browsing other than they could be system error codes?

3. Switched from PHP5 to PHP5.3 with no success, also changed PHP INI file on 5.3 to no avail.

4. Switched from PHP5.3 to PHP5.4 changed the INI file, no success.

5. Tried the upload script by logging into remote server, navigating to the page and it worked perfectly!

6. Tried the script on various different clients, same result didn't work.

7. Tried a few different scripts same result.

The actual PDF file seems to go into the TEMP directory and the script hits 100% before throwing out the 500 error.

Please help! I feel like I'm going crazy, been stuck on this since last Friday, if I see another 500 Internal Server Error, I think I'll go crazy.

Thanks