Sounds like random noise. There is RF every where.

I think the internal "slicing" capacitor is wondering around giving false data.

If this is the case, depending on what you are going to use this for the solution can pretty easy.

If you are sending commands for a remote control the easy way is to have something like
Code:
SERIN ReciverPIN,T1200,[9],Counter
IF Counter = ??? THEN 
XYZ 
ELSE
QRS
If you are sending data like what you are now, you may need to set up a way to verify the data. Some sort of encoding / checksums...

The Linx web site has some info on this and dhoustion has a protocal on his web site.