Cannot save my document in Excel format

Hello

I am working on a rather large document. The source file is an Excel document. I have no problem working in Studio with the translation, but when I try to save the target in Excel, I keep getting the same message that the name is longer than the allowed 31 characters and that I need to change the name. So, I changed the name, but that did not help me. Now I started all over, renaming the source document to checklist-eng, i.e. 13 characters! I opened a new single document for translation, filled it with the text from my TM, saved it and then tried to save the target as checklist-eng-da. No luck! Same message again.  

Failed to save target content: The translated text length for the worksheet name is longer than the allowed 31 characters. Please change the text and try again. 

Help!