That usually means the take up reel isn't working. No take up reel, no counter. VCR thinks tape is ended and ejects it then. All it needs is cleaning. Clean the idler wheel well with regular alcohol and you should be good to go. Start to finish takes less than 30 mins. Good luck.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix cassette recorders.