ASP.Net on actual site yields security exception - asp.net

Question

I deleted and recreated the subdomain for an ASP.Net site. I then uploaded the files, but when I go and open a browser, I get a security exception that states that I have to modify the application's configuration file to grant trust. Sadly, the error message does not say the file that caused the issue, the trust that is a problem, or anything that I can see.
Here is what I see:
Server Error in '/' Application.
Security Exception
Description: The application attempted to perform an operation not allowed by the security policy. To grant this application the required permission please contact your system administrator or change the application's trust level in the configuration file.
Exception Details: System.Security.SecurityException: Request for the permission of type 'System.Security.Permissions.FileIOPermission, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.
Source Error:
[No relevant source lines]
Source File: App_Web_iqeawexe.0.cs Line: 0
Stack Trace:
[SecurityException: Request for the permission of type 'System.Security.Permissions.FileIOPermission, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.]
System.Security.CodeAccessSecurityEngine.Check(Object demand, StackCrawlMark& stackMark, Boolean isPermSet) +0
System.Security.CodeAccessSecurityEngine.Check(CodeAccessPermission cap, StackCrawlMark& stackMark) +31
System.Security.CodeAccessPermission.Demand() +46
System.Reflection.RuntimeAssembly.VerifyCodeBaseDiscovery(String codeBase) +118
System.Reflection.RuntimeAssembly.GetName(Boolean copiedName) +69
System.Reflection.Assembly.GetName() +12
DevExpress.Web.ASPxClasses.Internal.HttpUtils.<get_DXValidatorType>b__0(Assembly i) +9
System.Linq.WhereArrayIterator`1.MoveNext() +55
System.Linq.Enumerable.FirstOrDefault(IEnumerable`1 source) +4216052
DevExpress.Web.ASPxClasses.Internal.HttpUtils.get_DXValidatorType() +120
DevExpress.Web.ASPxClasses.Internal.HttpUtils.GetValueFromRequest(HttpRequest request, String key, Boolean skipValidation) +25
DevExpress.Web.ASPxClasses.Internal.HttpUtils.GetValueFromRequest(String key, Boolean skipValidation) +60
DevExpress.Web.ASPxClasses.Internal.MvcUtils.get_CallbackName() +79
DevExpress.Web.ASPxClasses.Internal.RenderUtils.IsAnyCallback(Page page) +51
DevExpress.Web.ASPxClasses.Internal.ResourceRegistrator.EnsureResourcesSynchronized(Page page) +55
DevExpress.Web.ASPxClasses.Internal.ResourceRegistrator.RegisterResource(Page page, ResourceData resource, Boolean useStandardRegistration) +19
DevExpress.Web.ASPxClasses.ASPxWebControl.RegisterHoverIncludeScripts() +84
DevExpress.Web.ASPxClasses.ASPxWebControl.RegisterClientIncludeScripts() +72
DevExpress.Web.ASPxClasses.ASPxWebControl.OnPreRender(EventArgs e) +96
DevExpress.Web.ASPxClasses.ASPxDataWebControlBase.OnPreRender(EventArgs e) +32
System.Web.UI.Control.PreRenderRecursiveInternal() +103
System.Web.UI.Control.PreRenderRecursiveInternal() +175
System.Web.UI.Control.PreRenderRecursiveInternal() +175
System.Web.UI.Control.PreRenderRecursiveInternal() +175
System.Web.UI.Control.PreRenderRecursiveInternal() +175
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +8431
System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +253
System.Web.UI.Page.ProcessRequest() +78
System.Web.UI.Page.ProcessRequestWithNoAssert(HttpContext context) +21
System.Web.UI.Page.ProcessRequest(HttpContext context) +49
ASP.default_aspx.ProcessRequest(HttpContext context) in App_Web_iqeawexe.0.cs:0
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +100
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +75
Thoughts?

Answer 1

The problem turned out to be an defect in DevExpress release. The release posted on July 8th broke websites using Medium Trust model. They posted a hotfix.
Here is what DevExpress wrote me: "We have already fixed this issue in the context of the System.Security.Permissions.FileIOPermission exception after updating to DevExpress 2013.1.5 in Medium Trust environment ticket. I suggest that you download a fix and check whether or not the problem persists."
I was not expecting a big company to not do thorough testing, which is what made this bug hard to track down.