Sharepoint - Adding ScriptLink for js file to my Visual Webpart causes error: "Cannot make a cache safe URL for...."

Try removing the LAYOUTS from the ScriptLink

<SharePoint:ScriptLink ID="ScriptLink5" runat="server" Name="SprocketComplete/js/sprocketComplete.js" Localizable="false"/>

Microsoft.SharePoint.WebControls.ScriptLink+ScriptLinkInfo has

public string ToScriptUrl(Page page)

Which does

return SPHttpUtility.UrlPathEncode(SPUtility.MakeBrowserCacheSafeLayoutsUrl(filename, this.Localizable), true);

So the base url is /_layouts/