member join issue

I am getting this warning when members join my site. Does anyone know what this is or how to fix it?

Warning: fopen(/home/davisfam/public_html/cache/user3.php) [function.fopen]: failed to open stream: Permission denied in /home/davisfam/public_html/inc/profiles.inc.php on line 660

Warning: fopen(/home/davisfam/public_html/cache/user3.php) [function.fopen]: failed to open stream: Permission denied in /home/davisfam/public_html/inc/profiles.inc.php on line 660

Warning: fopen(/home/davisfam/public_html/cache/user3.php) [function.fopen]: failed to open stream: Permission denied in /home/davisfam/public_html/inc/profiles.inc.php on line 660
Join complete
Congratulations!

Your account has been successfully confirmed and activated.
You can log into your account now.

Check permissions of the /cache folder  .....  should be 777  ..... 
.

Thank you very much it worked

If anyone has gotten a database query error for member join like I just did after fixing above issue. I have a simple fix. Member join field for sex must be filled in and made mandatory in order for me to avoid this error joining my site. Does anyone have another way around this issue?