Problems with echo and eval WHY is this a PHP issue or vbulletin only? Please explain

[whitejeep]

Can you help me explain but i have been useing echo and print_r and var_dump to debug my PHP in the past i have tried in the same in vbulletin. And have run to a problem and maybe you might have some other sujestion since i am new to PHP and not new to programing its self and so far find the tools alittle on the premitive side for debugging in PHP and allways looking for new ways to debug my scripts with tools provided in the lanagiage ussly help.

So how do I get around this basic problem - I have found that when i do a echo and have in my PHP script a eval(); like below I have to comment the eval out if i what to print my debug messages - why is this the case and how do i get around the problem any ideas. Note: if I do not use my debug statements in the PHP in vbulletin I do get the correct templete shown on the page but if I try to put debug code in then the page is blank and no debug messages show up either - WHY - Now if I comment out the eval then my debug statements show up but the templete does not. So far the only things that works is to paste the HTML that is redered on a page by view the source and pasting the HTML below the PHP code and my debug code and templete does show.

echo 'This is a test message';
echo "<br>";

// eval('print_output("' . fetch_template('testpage') . '");');

I also use not only echo messages but var_dump and print_r as well as echo to debug my PHP vbulletin script - as you know i am kind of new to this PHP stuff not to mention the vbulletin stuff and the why things are done in vbulletin I do not know if this is just in vbulletin or a standard PHP and useing stardard output problems - if you could explain why and how I should get around the problem - if i was using another language i might use some # defines to get around the problem but i do not see that supported in PHP as of yet.

THANKS