Hi Polter,
debug.log is a logfile which I've never seen before in SiteScope, but in the end I found a place in the source code where we use it.
Do you have a reference to debug.log in the log4j.properties file?
You didn't post any entries, so I cannot see whether you see INFO / ERROR message in there, or DEBUG messages.
So first check if the messages are DEBUG message or plain errors, warning or info messages, like
.. (TextUtilsBase.java:599) DEBUG - Spliting String:SetProperty category good ..
.. (PerfMonitorMeasurementsTreeConstructor.java:120) ERROR ..
In any case, check in log4j.properties if you can find an entry with "com.mercury.sitescope.util" or even "com.mercury.sitescope.util.DebugWatcher" and verify its setting.
Depending of the message which are logged there you might need to change the loglevel to INFO or alike.
Greetings
Siggi