So you read about the new PowerShell Script Browser add-on that was released but now you get this error:
This because the add-on builds on the Culture en-US and right now does not work with for example sv-SE which is my culture I use in my Windows
If I first change to en-US and then start ISE and then change to sv-SE it works nicely,
It has been reported and hopefully it will come an update that corrects it
good luck in your explorations of the wonderful world of technet scripts inside ISE!