I need recommendations for good application servers for monitoring and debugging PHP and Mysql running on linux. It should have a GUI, query profiling (log slow queries etc.) and capture PHP errors with environment coniditions.
I am aware only of the Zend Platform that provides those features and I'm looking for alternatives.
I don't have a good answer for you, but as far as I know Zend Platform really is the only PHP app server that does everything you list, with an integrated reporting GUI. My background is doing pretty serious enterprise PHP stuff (clustered app and DB stacks) for nearly a decade, following the space closely, and running an Alexa top-1000 site.
Now I'll waste a paragraph pointlessly stating what you probably already know. :) You can do all the things you list -- log PHP errors with request/environment data, do MySQL slow query logging, and do analysis and application profiling -- relatively easily without Zend Platform from the CLI, and I've always done it by building logging hooks into the application, and then things like shell scripts, Mon and Monit for alerts/status GUI. But that's because my experience with really high-demand applications is scaling/clustering a single app or stack -- versus running servers where there are lots of random apps/scripts running, which is where I would think Zend Platform would really shine. If you're into SNMP, you can set that up then use a GUI client to do a lot of what you're talking about, but again, that's not the same level of "out of the box" that Zend provides, either.
I modded your question up and will be really interested if you get a better answer about a Zend Platform alternative, but I don't think there's an integrated server product that comes close.