I believe you accidentally deleted the coma after the "DownloadZipURL" line(see image).
The good thing is: I'll never make this error again
But the bad thing is: It does not seem to fix the problem. I uploaded the corrected update.json file about an hour ago, but OPM still displays the old version 0.1.0
BTW: What is the "repository filename"? The name of the zipped package in the Lazarus repository, or the name in the sourceforge repository? In the latter case the filename would be wrong: it would be spktoolbar-0.1.zip for the current version displayed (and spktoolbar-0.1.1.zip for the new version)