I had a customer who could not get the blog module to work on our shared hosting with the above error.
I thought it would be helpful to share the issue with the community to enable you to run Silverstripe on many main stream hosts.
As of PHP5, a security hole which allowed scripts to set the include paths over the Admin level settings has now been removed.
As such the _config under Sapphire which tries to set the parsers path fails.
Depending on host there are a few ways to fix it.
1) Remove or comment out any include path in php.ini
2) Remove or comment out any include path in .htaccess
3) Add the actual path into the vhost / php.ini file.
Many hosts, us included, set PEAR paths at server level and this ultimately breaks Silverstripe. This can be fixed by removing or setting the path at Admin level.
I hope this will help reduce 'hair pulling' for many who wonder why they get the 'something bad has happened' warning after adding the blog folder.
You will need to use developer mode to see the error which is detailed elsewhere on this forum.