Description:
------------
When px_set_blob_file is called with a blob file that isn't reffered to absolutely, or that is in a "good" spot (the current WD, whatever that may be generally), then it isnt found - this is dramatic when working in apache.

strace reveals that there is no path prepended in that case, although this happens in px_open_fp - probably the code is omitted in px_set_blob_file.

A Workaround obviously is to specify the path absolutely.

This is -extremely- confusing nevertheless (php finds file, pdoxlib does not - wtf?)

Reproduce code:
---------------
make a subdirectory, put X.DB and X.MB there. Then, make a script along the lines of:

$px=px_new();
$fp=fopen('X.DB','r');
px_open_fp($px,$fp);
px_set_blob_file($px,'X.MB');

Expected result:
----------------
(no error message)

Actual result:
--------------
Fatal error: px_set_blob_file() [<a href='function.px-set-blob-file'>function.px-set-blob-file</a>]: Could not open blob file. in /var/www/Script/script2.php on line ...