First of all: cpg1.4.12 is outdated. Most recent stable release currently is cpg1.4.16. Upgrade!
Second: I told the thread starter of the thread you refer to what he should have done. The same piece of advice applies to you as well:
In fact, this thread started wrong in the first place - you should do exactly as suggested in the upload troubleshooting section of the docs if you have upload issues.
You may have read the upload troubleshooting section of the docs, but you definitely haven't done as suggested there.
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If you want to find out what you did wrong, read up the upload troubleshooting section extra carefully.
You have made absolutely the same mistakes that mipavluk has made in his posting. We do not want you to post debug_output. We don't want you to enable notices_display. We want you to read the
upload troubleshooting section of the docs and do as suggested there. For your ease of use, let me quote that section for you, highlighting the bits you obviously failed to read:
4.11.4 Upload troubleshooting
If you are experiencing issues with coppermine's upload process, temporarily change your coppermine settings as suggested below to get more detailed error messages. This applies to all upload methods, not only HTTP uploads.
* Log in as admin
Go to your coppermine page and log in as admin
* Go to the config screen
* Scroll to the bottom of the page
* Expand the "Maintenance settings" section by clicking on it
* Enable debug mode for everyone
(set Enable debug mode to "Yes: Everyone")
* Leave display of notices switched off
(notices are only meant for developers. If you have idea what they mean, leave them off.)
* Save the new settings by clicking on "Save new configuration"
* Go to the "groups" panel
* Set the upload form configuration for all groups to "Single file uploads only"
1. set File upload boxes to "1" (1)
2. set URI upload boxes to "0" (2)
3. set No. of boxes to "fixed" (3)
# Save your new settings
(click on "Apply Modifications")
Then try to upload (using http uploads, even if you experienced troubles using another upload method) - you should get a more detailed error message that tells you what exactly goes wrong with your uploads. If the error message doesn't mean anything to you, search the support board for the error message you get.
4.11.5 Asking for support on upload issues
When asking for support on the coppermine forum, post a link to your site and a test user account (the test user mustn't be in the admin group!) with upload privileges, with the above mentioned settings in place - this way, supporters can see the error messages as well. Do not post debug_output unless requested. If you want fast results, you should disable admin approval for the group the test user is in, so supporters can tell instantly what is wrong without needing to double-check.
When people have issues with uploading and decide to post their question on the Coppermine support board, they usually are told to read this upload troubleshooting section. Many of them fail to do so properly, which results in frustration both for users as well as supporters. To make this absolutely clear: the above mentioned steps are absolutely mandatory, no matter what skill level you have, no matter what upload method you have troubles with. Failing to do exactly as suggested will result in your request for help being ignored. Yes, this applies to you. We mean it!