AvP[V\[X and I can't input the rest of it

What is this error message telling me?

Adobe Reader was already open.  I double clicked a file in Windows File Explorer, a fillable PDF file.  Adobe Reader displayed this error message twice.  I clicked OK twice.  After that, Adobe Reader opened a new tab and displayed the file.  I haven't tried filling and saving yet.

Adobe Acrobat Reader DC, AGM Version 4.030.00115.  Windows 10 21H2 64-bit with all updates, 32GB RAM, 4TB hard drives, etc.  Reader and Windows are both Japanese because I used to live in Japan.