If you have a SharePoint 2013 farm configured to support Business Intelligence and you get the following error message when you try to access a PowerPivot Gallery, most likely is because you recovered / rebuild your farm, or you have added an additional front-end server.

“System.IO.FileNotFoundException: The file /_controltemplates/15/PowerPivot/ReportGalleryView.ascx does not exist.
at Microsoft.SharePoint.ApplicationRuntime.SPRequestModuleData.GetWebPartPageData(HttpContext context, String path, Boolean throwIfFileNotFound)
at Microsoft.SharePoint.ApplicationRuntime.SPVirtualFile.CalculateFileDependencies(HttpContext context, SPRequestModuleData basicRequestData, ICollection& directDependencies, ICollection& childDependencies)
at Microsoft.SharePoint.ApplicationRuntime.SPDatabaseFile.EnsureDependencies(HttpContext context, SPRequestModuleData requestData)
at Microsoft.SharePoint.ApplicationRuntime.SPDatabaseFile.EnsureCacheKeyAndViewStateHash(HttpContext context, SPRequestModuleData requestData)
at Microsoft.SharePoint.ApplicationRuntime.SPDatabaseFile.GetVirtualPathProviderCacheKey(HttpContext context, SPRequestModuleData requestData)
at Microsoft.SharePoint.ApplicationRuntime.SPVirtualPathProvider.GetCacheKey(String virtualPath)
at System.Web.Compilation.BuildManager.GetVPathBuildResultFromCacheInternal(VirtualPath virtualPath, Boolean ensureIsUpToDate)
at System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate)
at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate)
at System.Web.Compilation.BuildManager.GetVirtualPathObjectFactory(VirtualPath virtualPath, HttpContext context, Boolean allowCrossApp, Boolean throwIfNotFound)
at System.Web.Compilation.BuildManager.CreateInstanceFromVirtualPath(VirtualPath virtualPath, Type requiredBaseType, HttpContext context, Boolean allowCrossApp)
at System.Web.UI.PageHandlerFactory.GetHandlerHelper(HttpContext context, String requestType, VirtualPath virtualPath, String physicalPath)
at System.Web.HttpApplication.MaterializeHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()”

The fix is to deploy again powerpivotfarm14solution.wsp, powerpivotfarmsolution.wsp, powerpivotwebapplicationsolution.wsp. Installing PowerPivot for SharePoint is not enough. You must redeploy these WSPs anytime you add a new front-end server to your farm.

In my case it was about adding a new front-end server to the farm and the solution was simple:

Add-PSSnapin Microsoft.SharePoint.PowerShell
cd "C:\Program Files\Microsoft SQL Server\110\Tools\PowerPivotTools\SPAddinConfiguration\Resources\"
. .\ConfigurePowerPivot.ps1
Add-SPSolution -LiteralPath 'C:\Program Files\Microsoft SQL Server\110\Tools\PowerPivotTools\SPAddinConfiguration\Resources\powerpivotfarmsolution.wsp'
Add-SPSolution -LiteralPath 'C:\Program Files\Microsoft SQL Server\110\Tools\PowerPivotTools\SPAddinConfiguration\Resources\PowerPivotFarm14Solution.wsp'
Add-SPSolution -LiteralPath 'C:\Program Files\Microsoft SQL Server\110\Tools\PowerPivotTools\SPAddinConfiguration\Resources\powerpivotwebapplicationsolution.wsp'
DeployFarmSolution $false
DeployWebAppSolutionToCentralAdmin $false
Install-SPFeature -path PowerPivotFarm -Force
Install-SPFeature -path PowerPivotFarm -Force -CompatibilityLevel 14
Install-SPFeature -path PowerPivotCA -Force
InstallSiteCollectionFeatures

Don’t worry if the lines 4, 5, 6 are throwing exceptions during execution – most likely is because you already have the PowerPivot WSPs added to your farm. The other commands will take care of your problem.
Please adjust the paths according with your installation (in the above section code I use the default installation path).