The error

SP2-0552: Bind variable "B2" not declared.

can arise when using incorrect declarations in your SQL scripts.

For example, I had the follwing in a script:

var B2 DATE;
EXEC :B2 := to_date('22.02.2018','dd.mm.yyyy');

For sqlplus to accept this string, you need to declare your string as VARCHAR2, even though you intend to use datatype DATE in your query.

Declare it as VARCHAR instead:

var B2 VARCHAR2(10);