I installed AMPPS 3.7 to C:\dev, selected the php_intl.dll extension, and restarted Apache. Got this error:
PHP Warning: PHP Startup: Unable to load dynamic library 'C:/dev/Ampps\\php\\ext\\php_intl.dll' - The specified module could not be found.\r\n in Unknown on line 0
The file does exist in this location, but the concatenated string contains an invalid "\\", which is messing up the path in Windows.