Not an answer to the issue, but rather some set of ideas you might start with..
 The files you're opening in Studio (irrespective of format) are common to have not only text but also other data, i.e. pictures, illustrations, shapes, diagrams and so on. Studio needs to handle those stuff too to 'recollect' your target files back, once the translation is done. To handle them right it needs to know their properties and parse them respectively. My guess is that your file(s) have some objects (there might be 5 of them, but I'm not sure) or some single object, 5 properties of which it (Studio) cannot get correctly. Hence the issue comes. The best solution would be consulting Tech support to have them look into your files (you might try to contact them via Solution Finder then selecting

Download and Installation Problems >
  I use SDL Trados Studio and/or SDL Multiterm 2009, 2011, 2014 or 2015. >
   The installation went fine, but now I get an error message when opening or using the program. >
    The problem occurs in SDL Trados Studio 2011 / 2014 / 2015.. > 
     None of the articles resolved my problem.

[Yes, I know, via longa et saxosa]), but I guess having PSMA is a good idea for such a complex situation. Yet I guess you might try to investigate your files yourself for some specific/irregular peculiarities or even blank attributes as compared to other files you've already happen to have translated.
I don't remember any KBs to describe this issue yet.

Update:
Are you sure your excel files are really of that bilingual file type? The thing is that Studio prioritizes this or that file type depending on what you have in 'File - Options - File types' set higher/(de)selected before opening the files / creating translation projects.

Not an answer to the issue, but rather some set of ideas you might start with..
 The files you're opening in Studio (irrespective of format) are common to have not only text but also other data, i.e. pictures, illustrations, shapes, diagrams and so on. Studio needs to handle those stuff too to 'recollect' your target files back, once the translation is done. To handle them right it needs to know their properties and parse them respectively. My guess is that your file(s) have some objects (there might be 5 of them, but I'm not sure) or some single object, 5 properties of which it (Studio) cannot get correctly. Hence the issue comes. The best solution would be consulting Tech support to have them look into your files (you might try to contact them via Solution Finder then selecting

Download and Installation Problems >
  I use SDL Trados Studio and/or SDL Multiterm 2009, 2011, 2014 or 2015. >
   The installation went fine, but now I get an error message when opening or using the program. >
    The problem occurs in SDL Trados Studio 2011 / 2014 / 2015.. > 
     None of the articles resolved my problem.

[Yes, I know, via longa et saxosa]), but I guess having PSMA is a good idea for such a complex situation. Yet I guess you might try to investigate your files yourself for some specific/irregular peculiarities or even blank attributes as compared to other files you've already happen to have translated.
I don't remember any KBs to describe this issue yet.

Update:
Are you sure your excel files are really of that bilingual file type? The thing is that Studio prioritizes this or that file type depending on what you have in 'File - Options - File types' set higher/(de)selected before opening the files / creating translation projects.