When you're calling the sub either get rid of the parentheses like this,Conect hServer, hpool, vServerName, vUserName , vPassword , hUser
or, leave the parentheses and use the CALL keyword, like this,
Call Conect(hServer, hpool, vServerName, vUserName , vPassword , hUser)
You were getting the error because it was expecting a return value from a function to be assigned to a variable such as,
myConString = Conect(hServer, hpool, vServerName, vUserName , vPassword , hUser)