I just applied patch 6788 successfully and now I'm trying to apply patch 7405, but it gives me this error:
bash PATCH_SUPEE-7405_CE_1.9.2.1_v1.1-2016-02-23-07-42-31.sh
Checking if patch can be applied/reverted successfully...
ERROR: Patch can't be applied/reverted successfully.
patching file app/code/core/Mage/Adminhtml/Helper/Sales.php
Hunk #1 FAILED at 121.
1 out of 1 hunk FAILED -- saving rejects to file app/code/core/Mage/Adminhtml/Helper/Sales.php.rej
patching file app/code/core/Mage/Core/Model/Config.php
Hunk #1 FAILED at 1642.
1 out of 1 hunk FAILED -- saving rejects to file app/code/core/Mage/Core/Model/Config.php.rej
patching file app/code/core/Mage/Sales/Model/Quote/Item.php
Hunk #1 FAILED at 507.
1 out of 1 hunk FAILED -- saving rejects to file app/code/core/Mage/Sales/Model/Quote/Item.php.rej
patching file lib/Varien/File/Uploader.php
Hunk #1 FAILED at 216.
Hunk #2 FAILED at 538.
2 out of 2 hunks FAILED -- saving rejects to file lib/Varien/File/Uploader.php.rej
I tried replacing those files with the ones from the original Magento installation in case they were modified, but that didn't work.
How do I fix this? I'm using Magento version 1.9.2.1
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