I have been using
ReadFile <- try(read.dbc("C:/LocalPath/A_File.txt"))
I don't think that this can be done in R as the file is locked from C code. If you look at the function
dbc2dbf in this file you can see that it opens the file and tries to decompress it. Error "handling" is just printing the error and returning, but not closing the opened files which is bad practice imo. (Or a bug if you like to call it so.)
If you care you could open an issue on the github site of the project for this, maybe the author fixes the problem.
In case you are in desperate need (:P) of a working version I have compiled a quick fix for you that just calls fclose before it signals the error(s).
You can download it here. Just unpack and copy to your R library. Load with