Same here, nothing shows.
Uninstalled

Clear your forum cache if you are getting a blank screen.
If you run vBOptimise, clear cache.

Nothing shows, or you get that error?

Within the Membermap Main plugin

find
Add above it

Let me know if that works. Please note I had to CTRL+F5 on my browser to pick up the changes for some reason.

Now It works, but I can't see the map.

As I said, I need to ctrl + F5 on my browser in order to get it to show after Id had that error for some reason. You may need to do the same.

If you have the window where the map would be, check the longitude and latitude settings in the options.

EDIT: Thats not the issue in your case. Could you check your server error log and let me know what errors you are getting? You should def not be having that problem

Yes, I pressed crtl + F5, also I cleaned the cache.

I don't habe a webserver. Only a managed virtual server.

Did you read my reply?
Clear your forum cache or clear vBOptimise cache.
I was getting the same error, but after clearing the forum cache everything is working fine.

A website link would be useful.
Do you use Xcache/Varnish Cache or vBOptimise?

Now, it works.

On, my testserver it doesn't works.

Thx, all!