If you just downloaded 7.0.6 and noticed that new Slax 7.0.7 is released, you may download a tiny diff bundle. It is a 4KB big module for Slax which will add all newly changed files to your Slax. Download it and put it in /slax/modules/. The diffbundle is located here:
I didn't even test it, but it should work. It adds all the plasma-related config files so the panel no longer makes any problems. However I think you will need to remove changes.dat file in your Slax since most likely your existing Slax already overwrote the plasma*rc files and the diffbundle wouldn't have any effect (your changes would overide it). Alternatively you may unsquash the bundle to /slax/rootcopy.
For me, a 200MB download doesn't make any problem, so I would rather just download new fixed version in full. Now lets see if the fix really fixes the taskbar for all users. It is pretty tricky.
Maybe we will have 7.0.8 very soon :)