XF 1.1 forum is down, error message

[xml]

suddenly when i tried to browse my forums i get this error message:

An exception occurred: DateTime::modify() expects exactly 1 parameter, 0 given in /home/vbcom/public_html/community/library/XenForo/Locale.php on line 586
 
XenForo_Application::handlePhpError()
DateTime->modify() in XenForo/Locale.php at line 586
XenForo_Locale::getDayStartTimestamps() in XenForo/ViewRenderer/HtmlPublic.php at line 98
XenForo_ViewRenderer_HtmlPublic->renderContainer() in XenForo/FrontController.php at line 565
XenForo_FrontController->renderView() in XenForo/FrontController.php at line 156
XenForo_FrontController->run() in /home/vbcom/public_html/community/index.php at line 13

and when i try to login the admin CP am getting thos borwser message:

The website cannot display the page
HTTP 500
Most likely causes:
•The website is under maintenance.
•The website has a programming error.
What you can try:
 
Refresh the page.
 
 
Go back to the previous page.
 
 
More information

any idea what cause this issue?

 

[Digital Doctor]

Try refreshing the page.

 

[xml]

Try refreshing the page.

i did but didnt resolve the issue

 

[Digital Doctor]

contact your host.
did they upgrade php ?

It's a weird issue.
probably a server issue.

Lots of drupal reports of this php error.

Do you have XenAtendo ?

 

[xml]

contact your host.
did they upgrade php ?

It's a weird issue.
probably a server issue.

yup its weird and doesn't make sense, when things like this happen the last fix i can think of is to reboot the server and guess what? the f*%#$%ing error gone the forum is up again

 

[Digital Doctor]

Universal computer fix: Unplug, Plug back in.


(I didn't think you had that option)

 

[Jake Bunce]

That error is either a modified file (XenForo_Locale), or maybe a corrupt opcode cache like APC (a restart would have cleared the cache).