与nginx的PHP获取消息“没有指定输入文件。”

I am running a web server on a modified router, and I am having issues with PHP. I keep getting the message:

No input file specified.

I have searched and read a lot of the messages posted about this issue, but have not been able to resolve the issue. I am using NGINX as the web server, and if I use the built in PHP, it works no problem, but when I try to use the PHP installed from opkg, I get that message. The reason I want to use the PHP installed from opkg is that it is more updated and it includes mysqli, which the other one doesn't. Can someone please help?