Fatal error: ob_start()

[eluser]ilSignorCarlo[/eluser]
Today I upgraded CodeIgniter to the latest version, but this didn't solve the issue.
Anyway, I tried commenting ob_start() in Exceptions.php and now it loads the site, but in the end of the page it shows a lot of php errors, like this:

Code:

Severity: Notice

Message: Undefined variable: Z3cZ25Z3cZ2526Z3cZ27Z3c

Filename: home/index.php

Line Number: 1

Or like this:

Code:

Notice: ob_end_clean() [ref.outcontrol]: failed to delete buffer. No buffer to delete. in /web/htdocs/www.circolomagnolia.it/home/system/libraries/Exceptions.php on line 165

Don't know if this can help identifying the source of the problem.

The hosting service is Aruba and when I opened a ticket for this problem they say it may be caused by some javascript script. Is that possible? I mean, that is a php error.