Hi - there was an earlier thread from some time ago, talking about this problem, and for that particular user, it was due to some tags in that MP3 file that were not supported by Sonar at that time.
Here is the excerpt from that thread:
"The problem turned out to be that SONAR (as with Windows Explorer, Windows Media Player and many other applications) does not yet support ID3v2.4 tags, which is what Foobar2000 writes by default. ID3v2.3 tags are OK.
wormser's workaround was to go into the advanced preferences for Foobar and uncheck the "use padding" option, which actually does more than suppress string padding. It effectively causes Foobar to write ID3v2.3 tags. "
Wherever you got your MP3 file from, perhaps doing a conversion to another format then back to MP3 would eliminate the issue. Give that a shot - there are lots of freeware file converters out there - I use the conversion capabilities of YTD Downloader (I use it to download clips from YouTube and convert them to MP3 files).
I hope that helps,
Bob Bone