penders - 6:41 pm on Apr 12, 2013 (gmt 0)
FYI you don't need admin access to set full error reporting, just set this at the top of your script:
error_reporting(E_ALL | E_STRICT);
ini_set('display_errors','1'); // Unless you have error handler to pipe to file
...no output before this
An erroneous space, blank line, BOM (Byte Order Mark), zero-width space, etc. But, as you say, this is probably not the case as you would get errors with full error reporting set.