Bug server error on registration

Hi,

Today I got this error 8 times in 1 minutes:

Code:

Server Error Log
Error Info
ErrorException: Fatal Error: Cannot redeclare class XFCP_WidgetFramework_XenForo_Model_Permission - library/XenForo/Application.php(528) : eval()'d code:1
Generated By: Unknown Account, 25 minutes ago
Stack Trace
#0 [internal function]: XenForo_Application::handleFatalError()
#1 {main}
Request State
array(3) {
  ["url"] => string(229) "http://site.com.ir/api.php?hash=x7e8fca2dc0f896fd7cb4cb0031ba249&action=register&gender=female&email=someemail@gmail.com&username=%DA%A9%DB%8C%D9%87%D8%A7%D9%86+%D8%B2%D9%86%D8%AF&password=13701393&timezone=Asia/Tehran"
  ["_GET"] => array(7) {
    ["hash"] => string(32) "x7e8fca2dc0f896fd7cb4cb0031ba249"
    ["action"] => string(8) "register"
    ["gender"] => string(6) "female"
    ["email"] => string(23) "someemail@gmail.com"
    ["username"] => string(17) "کیهان زند"
    ["password"] => string(8) "13701393"
    ["timezone"] => string(11) "Asia/Tehran"
  }
  ["_POST"] => array(0) {
  }
}

any opinion will be appreciated.

 

Still getting it.

 

api.php is from this:
http://xenapi.net/

I have a custom android app + a custom site for my forum and I used that api + some of my own files to integrate custom site with my xf and have a single android app (to have i single registration for anyone.).
and its working fine for a long time. no problem at all. Just this time I get that error log in acp.