Change "an error is occurred" to "has occurred"

templates/status/200.tmpl

@@ -1,7 +1,7 @@
 {{template "base/head" .}}
 {{template "base/navbar" .}}
 <div id="body" class="container">
-	<p>An error is occurred : {{.ErrorMsg}}</p>
+	<p>An error has occurred: {{.ErrorMsg}}</p>
 	<p>Application Version: {{AppVer}}</p>
 </div>
-{{template "base/footer" .}}
+{{template "base/footer" .}}

templates/status/500.tmpl

@@ -3,8 +3,8 @@
 <div id="body" class="container text-center">
     <p style="margin-top: 80px"><img src="/img/500.png" alt="404"/></p>
     {{if .ErrorMsg}}<hr/>
-    <p>An error is occurred : {{.ErrorMsg}}</p>{{end}}
+    <p>An error has occurred: {{.ErrorMsg}}</p>{{end}}
     <hr/>
     <p>Application Version: {{AppVer}}</p>
 </div>
-{{template "base/footer" .}}
+{{template "base/footer" .}}