HELP! Can’t install module on live site - EE thinks the file is missing!

I have a new module named “Vouchers”. It works fine on my development site, and I am able to install and uninstall it via the Modules page.

But when I put the files live and try to install the module on the live site, I get the following error:

“Unable to locate the files needed to install this module”

What I have tried so far:

• Checked that the mcp.vouchers.php file is on the server and in the right place
• Checked and changed file permissions on that file
• Tried manually installing the module by adding an entry to the exp_modules table; I then get the same error when trying to access its CP page
• Tried accessing the file directly via ssh: “php mcp.vouchers.php”; I get the expected “Invalid file request” error message (so the file is present and the PHP is getting parsed)

I then tracked down where that error comes from (cp/cp.modules.php) and put some debug information in here:

if ( ! is_file($path))
{
  $OUT->fatal_error($LANG->line('module_can_not_be_found'));
}

I echoed the $path variable out - it matches exactly the correct server path (verified by copy+pasting into console).

I need to get this up and running today - do you have any suggestions for what might be wrong?

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