Danish... do you have a manual for the Compiler? If you haven't, then it's time you downloaded one. Go to the MeLabs website and find it.

You will then discover that the word SYMBOL dos not insert a value into the TRISB Register (as your comments suggest), but assignes a new NAME or ALIAS to a Variable, Register or PinName to make code more readable. You get an error because you are trying to redefine the same name TWICE... look the compiler is TELLING YOU this...

ERROR Line 13: Attempt to Redefine 'TRISB' (2SWITCH.BAS)

The compiler really is pretty good... it gives you a clue as to where your problem is, it's up to you to then analyse your line for the error.

If there is one thing I will recommend, is that you do not blindly copy other peoples code without checking LINE by LINE with the manual as to what it does.

PS... Patience. One posting of your question is fine... any more than that does not solicit any quicker responses.