KeyError

[YeFrank1]

I met a KeyError while running analyze 2.PRG, and I found many samples has the same error. I wonder how to deal with this problem, it seems like an error of finding the function call.
The error and traceback is here

reversing@icsref:$ analyze /home/ye/ICSREF/samples/PRG_binaries/GitHub/2.PRG
Working on /home/ye/ICSREF/samples/PRG_binaries/GitHub/2.PRG.
DONE: Hexdump generation
DONE: Header analysis
DONE: String analysis
DONE: I/O analysis
DONE: Find function boundaries
DONE: Function disassembly
DONE: Find dynamic calls
DONE: Find static calls

Traceback (most recent call last):
File "/home/ye/.virtualenvs/icsref/local/lib/python2.7/site-packages/cmd2.py", line 2476, in onecmd_plus_hooks
stop = self.onecmd(statement)
File "/home/ye/.virtualenvs/icsref/local/lib/python2.7/site-packages/cmd2.py", line 2675, in onecmd
stop = func(statement)
File "/home/ye/ICSREF/icsref/icsref.py", line 75, in do_analyze
self.prg = Program(filename)
File "/home/ye/ICSREF/icsref/PRG_analysis.py", line 107, in init
self.__find_libcalls()
File "/home/ye/ICSREF/icsref/PRG_analysis.py", line 281, in __find_libcalls
lib_name = self.libs_dict[jump]
KeyError: 21676
EXCEPTION of type 'KeyError' occurred with message: '21676'
To enable full traceback, run the following command: 'set debug true'`