Random flac files not converting -- "Error opening file"

[EthicalDilemma]

I'm running dBPoweramp Batch Converter 12.4 to convert .flac files to .mp3, and most converted cleanly with no errors. However, at least of couple of files in each folder did not convert, and I got the following error:

Error converting to mp3 (Lame), 'D:\shares\Music\lossless\Benedictine Monks of Santo Domingo de Silos\Chant II\Haec Dies Quam Fecit Dominus.flac' to 'D:\shares\Music\lossless\Benedictine Monks of Santo Domingo de Silos\Chant II\Haec Dies Quam Fecit Dominus.mp3'
Error opening file, check no other program has it open. [clDecoder::WriteIDTags]

There is a converted .mp3 file in the folder post-conversion process, but no tag information has been written to the converted file.

I have checked that the files are not open in any other application.

Thanks in advance for you help.

[LtData]

Anti-virus, maybe? Have yo utried disabling it and see if you still get the error?

[EthicalDilemma]

Anti-virus, maybe? Have yo utried disabling it and see if you still get the error?

Thanks for the suggestion. No, disabling anti-virus had no effect.

One strange thing I've discovered is that I can successfully convert these files one at a time by right-clicking on file in Explorer and choosing "Convert To," which takes me to the same configuration dialog I get to from the Batch Converter file selection dialog. But for some reason the Batch Converter mode trips up the conversion process in some way and causes the above error.

I have about 200 files left to convert, and I'd rather not do them one by one, so if you have other ideas please let me know.