This is an issue with vbSEO
. Our product works fine with vbulletin 4. I beleive there is a setting in the vbSEO
admin panel to disable that product on specific directories. You dont do it in an htaccess like you did in previous vbSEO
versions but they should have more information on this. There application in a nutshell is preventing our VB40 variable from being defined.