Not a new problem but one that has been around for some time with CPDN. One user using WSL recently reported it.

Process creation (../../projects/climateprediction.net/hadsm4_8.02_i686-pc-linux-gnu) failed: Error -1, errno=13
execv: Permission denied

A bit of searching of crashed tasks revealed that all the failures of this type apart from the WSL ones are using Virtual Box whether from Windows or not I don't know. At first sight, it looks to me like a python error message but given most of my programming experience is with algol60 and algolW that may be a red herring. Sadly, as far as I can determine none of the users with the error using VB have posted. Any ideas as to where to look for clues gratefully received. In the past I have seen this error on Macs but it is too long ago for me to know whether this was using any virtualisation or not. If I find one will check.

Edit:All the Ubuntu ones are showing VB on the computer details but this one and all others from same computer using Arch Linux isn't.

With reference to this problem which I am spotting occurs on a lot of tasks where the computer has the following when I look at the host's page,

Virtualization Virtualbox (5.2.42_Ubuntur137960) installed, CPU has hardware virtualization support and it is enabled
Operating System Linux Ubuntu
Ubuntu 18.04.5 LTS [4.15.0-135-generic|libc 2.27 (Ubuntu GLIBC 2.27-3ubuntu1.4)]

Does this mean it is running Ubuntu under VB or does it mean it is a Linux computer with VB installed and possibly in use or third possibility I suppose, is it impossible to tell?