I have this PHP error HELP! how can i fix this

<style> 
body { behavior: url("csshover3.htc"); }
.bbcode_hover { background-image: url('icons/bold.gif'); background-color: transparent; height: 20px; width: 20px; border: 0px; }
.bbcode_hover:hover { background-image: url('icons/bold_on.gif'); background-color: transparent; height: 20px; width: 20px; border: 0px; }
.bbcode_hover1 { background-image: url('icons/italics.gif'); background-color: transparent; height: 20px; width: 20px; border: 0px; }
.bbcode_hover1:hover { background-image: url('icons/italics_on.gif'); background-color: transparent; height: 20px; width: 20px; border: 0px; }
.bbcode_hover2 { background-image: url('icons/underline.gif'); background-color: transparent; height: 20px; width: 20px; border: 0px; }
.bbcode_hover2:hover { background-image: url('icons/underline_on.gif'); background-color: transparent; height: 20px; width: 20px; border: 0px; }
.bbcode_hover3 { background-image: url('icons/insert_hyperlink.gif'); background-color: transparent; height: 20px; width: 20px; border: 0px; } 
.bbcode_hover3:hover { background-image: url('icons/insert_hyperlink_on.gif'); background-color: transparent; height: 20px; width: 20px; border: 0px; } 
.bbcode_hover4 { background-image: url('icons/strikethrough.gif'); background-color: transparent; height: 20px; width: 20px; border: 0px; } 
.bbcode_hover4:hover { background-image: url('icons/strikethrough_on.gif'); background-color: transparent; height: 20px; width: 20px; border: 0px; } 
.bbcode_hover5 { background-image: url('icons/insert_picture.gif'); background-color: transparent; height: 20px; width: 20px; border: 0px; } 
.bbcode_hover5:hover { background-image: url('icons/insert_picture_on.gif'); background-color: transparent; height: 20px; width: 20px; border: 0px; } 
.bbcode_hover6 { background-image: url('icons/justify_center.gif'); background-color: transparent; height: 20px; width: 20px; border: 0px; } 
.bbcode_hover6:hover { background-image: url('icons/justify_center_on.gif'); background-color: transparent; height: 20px; width: 20px; border: 0px; } 
.bbcode_hover7 { background-image: url('icons/forecolor.gif'); background-color: transparent; height: 20px; width: 20px; border: 0px; } 
.bbcode_hover7:hover { background-image: url('icons/forecolor_on.gif'); background-color: transparent; height: 20px; width: 20px; border: 0px; } 
</style>

Code (markup):

 

>> Please specify what error are your exactly getting?

 

I have a based text game and when members try to send a mail everything works fine but this error show on the mail page.

 

>> Can you please share your website URL and where (which page) the error exactly occurs so that the developer can go through the issue?

 

I shared it in private check your inbox.

 

Thank you @hostechsupport for the help it worked.

@hostechsupport he was able to fix my issue.

In my game there is some casinos.
i want to make the casino owned by players and people can gamble on them, and the owner of the player will lose it to another player when the owner cash money is 0.
and the player who wins it will own it and keep going.