First you should upate to latest version which is v6.10
.0.1008. Your registration key should work also for this version.
If I understand you correct you want to run a folder compare on text files in a folder and you want to see all the differences between text files with identical names at once in one text compare window. Sorry, but that is not possible. You can only run a basic/full/smart folder compare and then double click on every line with not identical files to open an individual text compare session in a new tab for a file pair to see the differences of the 2 files. It is not possible to see all differences of all not identical files in one text compare window.
If you want to see all differences of all not identical files you have to merge the content of all files in folder 1 into 1 big text file and the content of all files in folder 2 into a second big text file and compare these 2 big text files. The script posted at Merge / combine / copy the content of text into a new file
may help you here. It's a good idea in your case to insert the name of the file from where a text was copied above the copied text. The script is already prepared for that task too. You just have to remove some //
to achieve that as written in the comments of the script.
Also possible is to create a batch file which runs UltraCompare Prof. with text compare on all file pairs with writing the compare results into 1 text file per file pair. Then you can merge the compare result files. See in help of UltraCompare Prof. the page with the command line options.