When you open your TISOFT project, those should come in with the code when you open the .vpu file. Do you have all of the other project file extensions in the same folder (can't remember the TISOFT extensions for rung comments and synonyms)?
Those .txt/.csv import mechanisms are for Excel or other DirectSOFT projects. TISOFT should "just work" (assuming you have ALL the files, NOT JUST THE .VPU files)
MyOldProj.vpu
Other MyOldProj project files:
MyOldProj.snn // synonym extension, whatever that is - can't remember
MyOldProj.lcm // ladder comment extension, whatever that is - can't remember
MyOldProj.vm // v memory data extension, whatever that is - can't remember
MyOldProj.??? // bunch of other extension files
Are you missing all these other "extensions"?