Just to let everyone know I resolved this myself.
On my server at least the code has a slight glitch in it. When the eshop_download_the_product() function is called within cart-functions.php a call is made to ob_end_clean() (around line 1440’ish)
This removes the topmost output buffer but my installation, at this point in the code, was actually 4 levels deep.
So I replaced the single call to ob_end_clean() with:
do {
ob_end_clean();
} while ( ob_get_level() );
This removes all of the nested output buffers and allows the file to download without issue. This will also help to solve any readfile() memory issues associated with the readfile being called while still being output buffered.
Hope it helps someone else.
Thanks – Jim
