It is a problem of Lazarus compiler which fails with KDE when an opendialog should be handled. Try to change KDE settings in System setup -> Appearance -> GTK+Appearance -> Widget style:

Instead of default 'QtCurve' theme use 'Raleigh' theme, the problem should disappear.

You need to have libstdc++5 installed!

The accompanying problem is the abonormally high CPU load. The problem is instant polling of non-existent (not responding) radio. Your radio setup is probably incorrect, possible a mess in the cqrlog.cfg. Try to downoad a default cqrlog.cfg from here and copy it into your /cqrlog/log_data folder. Backup before your old cqrlog.cfg if you want. The default cqrlog.cfg redirects all polling to the hamlib dummy radio (model=1] and the high CPU load should return to its normal values.

Then you should set up your radio again. Don't use a too low poll rate, a value of 300 is sufficient.

32 bit libraries must be installed! If not, please install bug-buddy.i386 and all the libstdc.i386 packages. Also hamlib 32bit version has to be installed.

go to Preferences -> Fonts and uncheck the 'Use default settings' option

and set fonts manually. Choose any font of your preference which is present in your system (you will see it in the font choice pulldown dialog 'Select font'). This fixes this problem.