Get-a-Post plugin and caching problem?

The good news is that the Get a Post plugin (https://guff.szub.net/2005/01/27/get-a-post/) is simple and elegant. The bad news is that for some reason it also seemed to create a caching problem of some sort that broke the login or logout functionality of my blog (clearing the browser cache briefly fixes it). I should have suspected something when I clicked the button to activate the plugin and it took me to a blank page. Anyone else experience this, or have clues as to why it happened?

UPDATE: Nevermind. On the second try, I downloaded the zipped plugin instead of using the .txt php file. That seemed to solve the problem. Carry on.