Introduction = I don't know Wordpress.
Find (edit) the .htaccess file in the root directory.
Check the .htaccess file in the Pulse directory and edit the paths.
Q - What does the tmp file contain?
Wordpress, do you need files from the "tmp" folder?
I don't know if Pulse 5.3.9 supports installation in a subfolder.
I had a problem installing "localhost/pulse539".
Installation of "localhost/pulse 5310" is successful.
Try using the older version (5.3.2) and then upgrade.