Error !

IndexError: list index out of range

72 navs = BaseNavigation(0).post_init(True).findWithChildren(sql)
73 if len(navs)>0:
74 tmpNav = [row for row in navs if Util.removeDisallowedFilenameChars(row.Title).lower().replace(' ','-') == pathrow[0].lower()]
75 currentId = tmpNav[0].Id
76 currentNav = tmpNav[0]
77 pathrow = pathrow[1:]
78 idx = 0
79 for row in pathrow:
80 filt = filter(lambda x:x.Parent == currentId,navs)
/home/flowerpo/public_html/CMS/live/WebEngine.py, line 75:
currentId = tmpNav[0].Id