Question about HP Audio Books

[Mich Verrier]

Hi All. OK Today I was listening to my HP Audio books red by Jim Dale. Now the audio books I have are on tape and here's my question: a bit be for the end of side 2 of tape 6 of OotP, the tape stopped, I ejected it from the player and it seemed to be fine, there was no ribbon spilling out everywhere or anything like that. So I put it back in and pressed rewind and it did and then I pressed play and nothing happened, I heard no sound, so then I took it out again and gave it a slap with my hand and then I put it back in and the tape worked fine. Now the same thing happend with tape 11 of GoF and I did the same thing and again it worked fine after I gave it a bit of a slap with my hand. Now can any one please tell me what is going on? Is this problem happening because my tape heads are dirty? Or what? I look forward to hearing people's thoughts on this little problem. 

from Mich Verrier.