Sorry, this was my fault - I uploaded the wrong file. I noticed when my site also went down due to it, and updated quickly!
You must have downloaded during the short-time that the bugged 1.2.5 was available. Please download the one now on the download page - it is the correct version.
This is the last release of v1 of Registration Validator. v2 will be complete sometime this week - it has been rewritten so that the antispam functions are all contained within one object, and a log object is also introduced with various different log settings. The advantage of this is that the antispam object can then be taken out of the plugin and put into another environment (i.e. none Joomla) very easily - currently, this isn't easy at all.
Sorry for the bugged upload, let me know if you have any problems with the current one (it is active on this site right now).