If by "main working folder" you mean under C:\Program Files, then yes, you're app is being denied access because everything under Program Files is ReadOnly to normal users.
You should be using a more suitable place to put data files, such as under C:\ProgramData\<mycompanyname>\<myappname>. These folders are writable by any user.
To get the path to the ProgramData folder, call
Environment.GetFolderPath()[
^] and use the
CommonApplicationData[
^] enum value as the parameter.
You'll have to build out the rest of the path, the \<mycompanyname>\<myappname> part. Use
Path.Combine()[
^] for that.