I have also updated Flash Player to last release.
I have Windows 7 64bit and VS2013.
My code:
<ext:GridPanel
ID="UploadGrid"
runat="server"
MinHeight="610"
MinWidth="750"
Frame="true">
<Store>
<ext:Store runat="server">
<Model>
<ext:Model runat="server" IDProperty="id">
<Fields>
<ext:ModelField Name="id" />
<ext:ModelField Name="name" />
<ext:ModelField Name="size" />
<ext:ModelField Name="status" />
<ext:ModelField Name="progress" />
</Fields>
</ext:Model>
</Model>
</ext:Store>
</Store>
<ColumnModel>
<Columns>
<ext:Column runat="server" Text="File Name" DataIndex="name" Width="300" />
<ext:Column runat="server" Text="Size" DataIndex="size" Width="60">
<Renderer Format="FileSize" />
</ext:Column>
<ext:Column runat="server" Text=" " DataIndex="status" Width="30">
<Renderer Fn="statusIconRenderer" />
</ext:Column>
<ext:Column runat="server" Text="Status" DataIndex="status" Width="60" />
<ext:ProgressBarColumn runat="server" Text="Progress" DataIndex="progress" />
</Columns>
</ColumnModel>
<TopBar>
<ext:Toolbar runat="server">
<Items>
<ext:MultiUpload
ID="MultiUpload1"
runat="server"
OnFileUpload="MultiUpload1_FileUpload"
FileDropAnywhere="true"
FileSizeLimit="25 MB"
FileTypes="*.*"
FileTypesDescription="All Files"
FileUploadLimit="100"
FileQueueLimit="0">
<Listeners>
<SwfUploadLoadFailed Fn="loadFailed" />
<FileSelected Fn="fileSelected" />
<UploadStart Handler="updateRecord(file.id, 'status', 'Sending');" />
<UploadProgress Handler="updateRecord(file.id, 'progress', bytesComplete / bytesTotal);" />
<UploadComplete Handler="updateRecord(file.id, 'progress', 1 );updateRecord(file.id, 'status', 'Uploaded' );" />
<UploadAborted Handler="updateRecord(file.id, 'status', 'Aborted');" />
<UploadRemoved Handler="var store = this.up('grid').store; store.remove(store.getById(file.id));" />
<UploadError Fn="uploadError" />
<FileSelectionError Fn="fileSelectionError" />
</Listeners>
</ext:MultiUpload>
<ext:ToolbarSeparator />
<ext:Button
runat="server"
Text="Start Upload"
Icon="Tick"
Handler="#{MultiUpload1}.startUpload();" />
<ext:Button
runat="server"
Text="Remove"
Icon="Delete"
Handler="removeUpload" />
<ext:Button
runat="server"
Text="Remove All"
Icon="Delete"
Handler="#{MultiUpload1}.removeAllUploads();" />
<ext:Button runat="server" ID="btnUploadClose" Text="Close" Icon="Cross">
<Listeners>
<Click Handler="fnUploadWindowClose();" />
</Listeners>
</ext:Button>
</Items>
</ext:Toolbar>
</TopBar>
</ext:GridPanel>