Hi,
The FTP allow to see the web server logs but not the PHP error log.
About Plesk, I don't understand Dutch, but I tried to find the PHP error log, without success ; I just find the web server logs (which does not contains any details about PHP messages).
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.