Why am I getting these error messages?

[jstap]

'GBPUSD' - undeclared identifier
'GBPUSD' - constant expected
'CurrentSymbol' - function not defined
'CurrentSymbol' - constant expected[0_1601206661423_PSAR EMA V1.1.mq4]
(/forum/assets/uploads/files/1601206662654-psar-ema-v1.1.mq4)

[jstap]

this is another version but for some reason I'm still getting these errors.

'GBPUSD' - undeclared identifier
'GBPUSD' - constant expected

0_1601220657349_PSAR EMA V1.2.mq4

[roar]

@jstap this should be string

[jstap]

@roar Thank you for the reply, could you please explain what you mean by should be string?

[jstap]

@roar got it thank you, you mean where it says double.

Thankyou