I am having a similar problem. I managed to log in to Sotadata and upload several tracks, but there is one specific track that fails to upload. When I try the upload, the pop-up “Checking uploaded file…” never goes away or finishes. I am using Chgrome on Win7. I loaded the track into several programs (MapSource, OziExplorer, an online gpx conversion utility) but neither produces a gpx that passes the checking stage at sotamaps upload.
73 Fric