thufir@dur:~$
thufir@dur:~$ /opt/pt/bin/./PacketTracer7
/opt/pt/bin/./PacketTracer7: error while loading shared libraries: libQt5ScriptTools.so.5: cannot open shared object file: No such file or directory
thufir@dur:~$
thufir@dur:~$ LD_LIBRARY_PATH=/opt/pt/lib /opt/pt/bin/./PacketTracer7
/opt/pt/bin/./PacketTracer7: error while loading shared libraries: libpng12.so.0: cannot open shared object file: No such file or directory
thufir@dur:~$
thufir@dur:~$ locate libpng12.so.0
/snap/core/4650/lib/x86_64-linux-gnu/libpng12.so.0
/snap/core/4650/lib/x86_64-linux-gnu/libpng12.so.0.54.0
/snap/core/4650/usr/lib/x86_64-linux-gnu/libpng12.so.0
/snap/core/4830/lib/x86_64-linux-gnu/libpng12.so.0
/snap/core/4830/lib/x86_64-linux-gnu/libpng12.so.0.54.0
/snap/core/4830/usr/lib/x86_64-linux-gnu/libpng12.so.0
/snap/core/4917/lib/x86_64-linux-gnu/libpng12.so.0
/snap/core/4917/lib/x86_64-linux-gnu/libpng12.so.0.54.0
/snap/core/4917/usr/lib/x86_64-linux-gnu/libpng12.so.0
/snap/gnome-3-26-1604/59/lib/x86_64-linux-gnu/libpng12.so.0
/snap/gnome-3-26-1604/59/lib/x86_64-linux-gnu/libpng12.so.0.54.0
/snap/gnome-3-26-1604/59/usr/lib/x86_64-linux-gnu/libpng12.so.0
/snap/gnome-3-26-1604/64/lib/x86_64-linux-gnu/libpng12.so.0
/snap/gnome-3-26-1604/64/lib/x86_64-linux-gnu/libpng12.so.0.54.0
/snap/gnome-3-26-1604/64/usr/lib/x86_64-linux-gnu/libpng12.so.0
/snap/vuze-vs/3/lib/x86_64-linux-gnu/libpng12.so.0
/snap/vuze-vs/3/lib/x86_64-linux-gnu/libpng12.so.0.54.0
/snap/vuze-vs/3/usr/lib/x86_64-linux-gnu/libpng12.so.0
thufir@dur:~$
显然是因为：
似乎安装了正确的库，但 CPT 需要旧版本 - 52 而不是 55。包含旧版本 libicui18n 的 Debian 软件包可在以下位置获取： http://security.ubuntu.com/ubuntu/pool/main/i/icu/libicu52_52.1-3ubuntu0.8_amd64.deb。
手动安装旧包：
thufir@dur:~/deb$
thufir@dur:~/deb$ wget http://security.ubuntu.com/ubuntu/pool/main/i/icu/libicu52_52.1-3ubuntu0.8_amd64.deb
--2018-07-07 04:30:57-- http://security.ubuntu.com/ubuntu/pool/main/i/icu/libicu52_52.1-3ubuntu0.8_amd64.deb
Resolving security.ubuntu.com (security.ubuntu.com)... 91.189.91.26, 91.189.91.23, 91.189.88.152, ...
Connecting to security.ubuntu.com (security.ubuntu.com)|91.189.91.26|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 6751362 (6.4M) [application/x-debian-package]
Saving to: ‘libicu52_52.1-3ubuntu0.8_amd64.deb’
libicu52_52.1-3ubuntu0.8_amd64.de 100%[==========================================================>] 6.44M 658KB/s in 10s
2018-07-07 04:31:07 (637 KB/s) - ‘libicu52_52.1-3ubuntu0.8_amd64.deb’ saved [6751362/6751362]
thufir@dur:~/deb$
thufir@dur:~/deb$ sudo dpkg -i libicu52_52.1-3ubuntu0.8_amd64.deb
[sudo] password for thufir:
Selecting previously unselected package libicu52:amd64.
(Reading database ... 186168 files and directories currently installed.)
Preparing to unpack libicu52_52.1-3ubuntu0.8_amd64.deb ...
Unpacking libicu52:amd64 (52.1-3ubuntu0.8) ...
Setting up libicu52:amd64 (52.1-3ubuntu0.8) ...
Processing triggers for libc-bin (2.27-3ubuntu1) ...
thufir@dur:~/deb$
thufir@dur:~/deb$ packettracer
Starting Packet Tracer 7.1.1
thufir@dur:~/deb$
结果相同。已安装的软件包包括：
sudo apt install libqt5webkit5 libqt5multimedia5 libqt5xml5 libqt5script5 libqt5scripttools5
答案1
从以下位置下载 libpng12 包这里，然后使用包管理器安装它，或者使用sudo dpkg -i <package>
我只需要安装这个包就可以工作。
答案2
这些软件包似乎已经解决了该问题：
thufir@dur:~/deb$
thufir@dur:~/deb$ sudo dpkg -i libicu52_52.1-3ubuntu0.8_amd64.deb libpng12-0_1.2.54-1ubuntu1_amd64.deb
(Reading database ... 186208 files and directories currently installed.)
Preparing to unpack libicu52_52.1-3ubuntu0.8_amd64.deb ...
Unpacking libicu52:amd64 (52.1-3ubuntu0.8) over (52.1-3ubuntu0.8) ...
Preparing to unpack libpng12-0_1.2.54-1ubuntu1_amd64.deb ...
Unpacking libpng12-0:amd64 (1.2.54-1ubuntu1) over (1.2.54-1ubuntu1) ...
Setting up libicu52:amd64 (52.1-3ubuntu0.8) ...
Setting up libpng12-0:amd64 (1.2.54-1ubuntu1) ...
Processing triggers for libc-bin (2.27-3ubuntu1) ...
thufir@dur:~/deb$
虽然我不确定这就是所需要的全部，但我也安装了其他软件包。