A Fatal error when I install the vbseo

Hi,
I'm a fresh man here.I just purchased vbseo and want to install it on my vbulletin 3.8.2 forum.
I followed the instruction:
A. Upload ALL the files in the 'upload' folder to your forum root folder.
B. License your vBSEO instance:

1. CHMOD 666 the 'vB-root/includes/config_vbseo.php' file.
2. Using your browser, visit: http://www.yoursite.com/vB-root/vbseocp.php.

......
But when I visit the page "http://www.yoursite.com/vB-root/vbseocp.php" the browser says:
Fatal error: Call to undefined function vbseo_linkback_getbandomains() in /(where my forum locate)/vbseocp.php on line 158

What's the problem?Thank you!
PS:There's no Chinese language surpport and my english is not good.Is it clear?

Hello,

please create .htaccess file in forums folder as described in installation instructions, then open vBSEO CP again.