Mystery weird Magento behaviors have finally been resolved… due to base64_decode being disabled by web hosting!

For a few months after i have upgraded to 1.6.x and to current 1.8.x, i have been facing the following issues/behavior in backend admin

1. Searching by fields in every view(Sales, Order, Catalog, etc) are not possible. All searches will return all result back. It seemed as if filter is not working!
2.  Dashboard graph is not working. It shows broken images regardless of any selection.
3. Reports that require to input a date range are not working. It keep showing ‘No Records’ even if i refresh the statistics
4. Even to the extend of doing fresh install of Magento (i tried 1.8.1) also gives the same errors above

And the clues i have are

1. phpinfo() shows that base64_decode has been disabled
2. Log files keep showing the following errors

Warning: base64_decode() has been disabled for security reasons  in MYAPP/app/code/core/Mage/Core/Helper/Abstract.php on line 365
Undefined index: title  in MYAPP/app/code/core/Mage/Reports/Model/Resource/Report/Collection.php on line 187
Warning: base64_decode() has been disabled for security reasons  in MYAPP/app/code/core/Mage/Core/Model/Encryption.php on line 144
Warning: base64_decode() has been disabled for security reasons  in MYAPP/app/code/core/Mage/Adminhtml/controllers/DashboardController.php on line 95
I never thought that the base64_decode php functions would indirectly cause all the problems i faced until i recently ask my web hosting company to enable it back.

To my surprise, all the functions are working properly now and i have finally close this issue.
If you encounter the above behaviors or issues, you may want to check if base64_decode has been disabled by your web hosting company. You can do so by creating a php file with a phpinfo() in it.