You need to change the value for "FcgidMaxRequestLen". The default value for this field is 128kb and hence you get "Internal server error" when you try to upload any file > 128kb.
To change the value, edit the file "fcgid.conf".
1. If you do not know the location of "fcgid.conf" on your system, run the following command to get the location of the file.
find / -type f -name "fcgid.conf"
2. Edit the file using your editor. E.g.
3. Add "FcgidMaxRequestLen 268435456" (128mb) to the file. You can set it to any desired value.
4. Restart web servers. e.g. Apache, Nginx