change PC? I had the same problem with my old computer, but i tried the method with another and it works

 

But, A friend's computer? The instalation of DevMenu is fast!

PD: DevMenu or Big Blue Box are unstable in my 3DS CFW. I prefer to use BigRedMenu.

 

That's a wifi connection problem. Some have solved it by running the web browser right away when the CFW starts. If it works then everything should be good.
Others just waited and kept trying until it finally worked. Some guy even said it worked after he performed a system format.

 

For me when I tried to install the CFW the hardest part was installing DevMenu.

Some of the tutorials suggest using a network monitoring / ping software to ensure that your laptop can reach the 3DS thru wifi.

For me it seems that my router settings is the root of my problem. So what I did instead is use my Android phone as a makeshift Wireless LAN (Hotspot) and connect my laptop and 3DS there, DevMenu installed successfully that way.

 

Two things I did before making it work:

• Remove any form of security (pass) on my WIFI connection. (You can afford it for a 5 minutes...)
• Deleted any other connection in CFW. The only one left was the connection to my pass-less SSID (thus in position 1).

To change the connection settings, you have to boot in CFW normal mode (without holding L), change your settings, and then boot back into server mode CFW (holding L) and try ctrclient connect. That worked for me (twice).