Horror! Error!

After installing the Taxonomy Browser, I tried to activate the TB-block and got the following error:

Fatal error: Call to undefined function: htmlspecialchars_decode() in /var/www/virtual/lancefestivalen.se/htdocs/modules/contribs/taxonomy_browser-6.x-1.3/taxonomy_browser/taxonomy_browser.module on line 359

Need I add that my entire site (running on D6.3) went down and was unaccessible until I deleted the module? I reinstalled the module and tried again - with the same result as soon as I tried to activate the module.

I guess it has something to do with the block, but I'm not sure...