Getting R6034 error when starting Eclipse for Java EE Developers

I use Windows 7 64-bit, Java 8.

I'm getting the following error:

and the following screen is left behind after the process is manually terminated:

I believe it started happening right after I installed a plugin from JBoss Tools - xulrunner.site - ­ Update Site that was supposed to help with 64-bit support for WildFly 8.

When I tried to configure a new project for GlassFish 4 I got the same error.

If my default workspace is not configured for any app server, I do not get the error.

I tried starting Eclipse with - clean parameter which did not help at all.

• What would be a reasonable troubleshooting path here?