apache error

[icy2003]

my php.ini

[ui]
extension=php_ui.dll

I download php-ui yesterday and my website acts as follows:
Internal Server Error
normal
Internal Server Error
normal
...
error and success is alternating, and when I note php-ui in php.ini, my website never shows error again.
this is apache log, I don't know if it has relations between apache and php-ui, but I think it may help:

[Wed Jan 23 15:14:08.070325 2019] [core:warn] [pid 12152:tid 744] AH00098: pid file E:/0_env/phpStudy/Apache/logs/httpd.pid overwritten -- Unclean shutdown of previous Apache run?
[Wed Jan 23 15:14:08.196326 2019] [mpm_winnt:notice] [pid 12152:tid 744] AH00455: Apache/2.4.23 (Win32) OpenSSL/1.0.2j mod_fcgid/2.3.9 configured -- resuming normal operations
[Wed Jan 23 15:14:08.196326 2019] [mpm_winnt:notice] [pid 12152:tid 744] AH00456: Server built: Jul  1 2016 16:42:20
[Wed Jan 23 15:14:08.196326 2019] [core:notice] [pid 12152:tid 744] AH00094: Command line: 'E:\\0_env\\phpStudy\\Apache\\bin\\httpd.exe -d E:/0_env/phpStudy/Apache'
[Wed Jan 23 15:14:08.203294 2019] [mpm_winnt:notice] [pid 12152:tid 744] AH00418: Parent: Created child process 5004
[Wed Jan 23 15:14:09.812294 2019] [mpm_winnt:notice] [pid 5004:tid 780] AH00354: Child: Starting 150 worker threads.
[Wed Jan 23 15:14:11.930571 2019] [core:error] [pid 5004:tid 2104] [client ::1:50235] End of script output before headers: index.php