Failed to open epub file

[sutrisnob45]

sometimes got this error when opening my ebook,

Traceback (most recent call last):
File "epr.py", line 1240, in
File "epr.py", line 1236, in main
File "curses_init_.py", line 102, in wrapper
File "epr.py", line 1122, in preread
File "epr.py", line 194, in initialize
ValueError: '../Text/cover.xhtml' is not in list
[4060] Failed to execute script epr

[wustho]

Hello there, sorry about that, but can you send the link to that problematic epub? Since I haven't encountered any such problem...