C# Noob Help Value cannot be null. Parameter name: String ASP.Net

Hello Code Guru community,

Let me start off by saying I am a noob when it comes to C# and Asp.net so any visual code help would be of great appreciation. I have a application/website which was built by someone else I am trying to tweak. However i keep receiving an error when I go to deploy the app. Below you will find the code. If something doesn't look right or if I am missing any information please let me know and I'll respond as soon as possible. Thanks in advance

Error Info:

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ArgumentNullException: Value cannot be null.
Parameter name: String

Line 7

Code:

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Line 5:  public abstract class MasterPageBase : System.Web.UI.MasterPage
Line 6:  {
Line 7:      private UserPermissions userPermissions = new UserPermissions();
Line 8:      public string SelItem { set; get; }
Line 9:      public RadWindowManager WindowManager_Notice

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UserPermissions Class

Code:

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namespace TmsAdministration
{
    public class UserPermissions
    {
        public string Email;
        public string FirstName;
        public bool IgnoreCache;
        public string LastName;
        public Dictionary<string, int> Roles;
        public string sAMAccountName;
        public bool UserIsInActiveDirectory;

        public UserPermissions();
        public UserPermissions(string sAMAccountName);
        public UserPermissions(string sAMAccountName, bool ignoreCache);

        public string FullName { get; }

        public int GetRoleId(string roleName);
        public string GetRoleName(int roleId);
        public ActiveDirectory.UserInformation GetUserManager();
        public List<string> GetUsersDirectReports();
        public int IsInRole(int roleId);
        public int IsInRole(string roleName);
        public virtual void RedirectIfNotInActiveDirectory(Page page, string redirectUrl);
        public virtual void RedirectIfNotInRole(Page page, string roleName, int requiredLevel, string redirectUrl);
        public virtual void RedirectIfNotInRoles(Page page, List<string> roleNames, List<int> requiredLevels, string redirectUrl);
        public void RefreshUser();
    }
}

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Master Page App Code

Code:

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using TmsAdministration;
using Telerik.Web.UI;
using System.Collections.Generic;

public abstract class MasterPageBase : System.Web.UI.MasterPage
{
    private UserPermissions userPermissions = new UserPermissions();
    public string SelItem { set; get; }
    public RadWindowManager WindowManager_Notice
    {
        get
        {
            return (RadWindowManager)this.FindControl("RadWindowManager_Notice");
        }
    }
    public RadWindowManager WindowManager_Error
    {
        get
        {
            return (RadWindowManager)this.FindControl("RadWindowManager_Error");
        }
    }
    public bool IsDevServer
    {
        get
        {
            return base.Request.Url.Host.Contains("localhost") || base.Request.Url.Host.Contains("wlfddev01.us.tms.local");
        }
    }

    public UserPermissions UserPermissions
    {
        get
        {
            return UserPermissions1;
        }

        set
        {
            this.UserPermissions1 = value;
        }
    }

    public UserPermissions UserPermissions1
    {
        get
        {
            return userPermissions;
        }

        set
        {
            this.UserPermissions2 = value;
        }
    }

    public UserPermissions UserPermissions2
    {
        get
        {
            return userPermissions;
        }

        set
        {
            this.userPermissions = value;
        }
    }

    public List<Common.EnumValue> UserLocations = null;
    public List<int> UserLocationsIds = new List<int>();
    public List<string> UserLocationsLabels = new List<string>();

    public MasterPageBase()
    {
        UserLocations = Common.Groups.GetUserLocations(UserPermissions);
        foreach (Common.EnumValue location in UserLocations)
        {
            UserLocationsIds.Add(location.Id);
            UserLocationsLabels.Add(location.Label);
        }
    }

    public abstract void SetTitle(string title);
    public abstract void DisplayHeaderLogo(bool visible);
}

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