On the 15 August 2019 Windows released an update that cause run time error 5 when trying to download application via U90Ladder.

Since then, they have released a fix for windows 7 and 10:

The relevant update for windows 7 is KB4512506.

The update to fix this issue (kb4517297)

Please see below link to Microsoft update and known issues:

https://support.microsoft.com/en-us/help/4512508/windows-10-update-kb4512508

Windows 10, version 1903

https://support.microsoft.com/en-gb/help/4512508/windows-10-update-kb4512508

Windows 10, version 1809

 https://support.microsoft.com/en-us/help/4511553/windows-10-update-kb4511553

Article can be found in the below link:

https://support.unitronics.com/index.php?/selfhelp/view-article/u90-ladder-and-runtime-error-5