What "powershell script provided by WinSCP" do you mean? There's no script for "syncing the directories and deleting the file downloaded" provided by default with WinSCP.
Do you rather mean that you have copied the code from this page?
https://winscp.net/eng/docs/library_example_delete_after_successful_download

The code requires the latest version of WinSCP. You are probably not using an up to date version.

Hello,

im trying to use the code for syncing the directories and deleting the file downloaded from the remote directory but i get a "Error: Unable to find type [WinSCP.RemotePath]" the file downloads but does not delete it from the remote path.

Im using the default powershell script provided by WinSCP

Thanks.