System.IO.DirectoryNotFoundException: Could not find a part of the path

I want to upload all the txt files from a folder. for uploading txt files to datagrid Iam using the following code.

path = (txtfilelocation.Text);//Folder path

        System.IO.DirectoryInfo dir = new System.IO.DirectoryInfo(path);

        foreach (System.IO.FileInfo f in dir.GetFiles("*.TXT"))

        {

            string[] aa = File.ReadAllLines(f.FullName);

            foreach (var item in aa)

            {

                DataRow dr = dt.NewRow();

                char[] delimiters = new char[] { '\t' };

                string[] parts = item.Split(delimiters, StringSplitOptions.RemoveEmptyEntries);

                for (int i = 0; i < parts.Length; i++)

                    {

                        DataColumn col = new DataColumn(parts[i]);

                        col.DataType = System.Type.GetType("System.String");

                        dt.Columns.Add(col);

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When I check in my local mechine it seems working with out error.

but when i try to run the same in a client  the following error

System.IO.DirectoryNotFoundException: Could not find a part of the path

please suggest how can I solve this Issue

Thanks In Advance