Hola,
Sólo tradúcelo:  
If you get an error like "1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '-20, 20' at line 1" then 
click here  for the fix! 
To get the osCommerce email system working change the following email settings in the "Configuration->E-Mail Options" section of the admin area. Change "E-Mail Linefeeds" to CRLF. Change "E-Mail Transport Method" to SMTP.  
 Cita:   The problem was that 1 tiny line of code wasn't PHP5 compatible. All you need to do is to open up admin\includes\classes\upload.php and edit the line on or about line #31 that says "$this = null;" to be "//$this = null;" (without speach marks) and that should fix the problem.
    *NOTA: ESTOS PROBLEMAS SE DIERON CON PHP 5 EN SERVIDOR WINDOWS.