Did you solve your problem?  Did you turn dev mode off and refresh the page?

I dont believe that error has anything to do with dev mode, you have a php parse error. Whatever you are trying to change or edit, you did it wrong and there is an error. 

Dave baby thanks so much for such a quick reply. I turned it off and the issue still remained for a while then went away by itself not sure what it was.

I was not doing anything to PHP only made plugin template html change. I mean I spend 1 hour getting server errors. I have plenty of users online and I think that with dev mode on and all of them trying to access the site that causes the server to go crazy.

I had to eventually use htaccess maintenance mode so that only my ip was allowed to access the site and finally was able to refresh the site.

If you have 1000 people online and you turn on dev mode there is no way it will go without errors.  

Your welcome, but that poses the question why are you turning on dev mode with 1000 people on line ? Would it not be better to wait for a slower time of night. :)

I would recommend a second installation "Test Site" for playing around. If something goes South, you don't affect your live site. When you know your change is working you can implement it on the live site during slow time, and having maintenance mode on. Possibly even announce the maintenance time ahead of time so the users will know the site will be down for that time.

Thanks guys. I though that switching to maintenance mode will take care of that found out the hard way it's not.

From now on I will simply use htaccess. I always test it on the localhost but wasn't expecting for the site to crash man still can't recover after I saw this erros with dev mode on and off I mean that looked like it was it I was already thinking about what a pain in the but is it going to be restore the site from backup.

Developers have to take this into account for sites that are very busy!

Please provide screenshot where you have this "Miles_fr" in your lang.php file

Seems like the array of values have a syntax error 

Ross baby my site gets decent amount of traffic so when I switched dev mode it started loading long time then server crashed I spend like this an hour or so then suddenly I got this error I freaked out and turned dev mode off but the error remained and was showing on every URL. Then simply disappeared.

It OK now!

Glad you got it sorted and let us know if you need more help.  

Dave 

:)

Well, I think you have ran into the memory limit, please check that with your hosting