Out of stack space error

1. You have not declared and typed your variables, so VB is assigning them the default type of Variant (16 bytes vs 2 for Integer and 4 for Long)
2. The variable intrade is used in each of the three procedures and it appears that you intended to have the value accessed and changed by each of the three variables; but, since it is undeclared, each procedure initializes a local variable of 16 byte Variant-type with no link to any previous value each time the procedure is called. You should declare it as Public at the top of the module (outside any procedure) and type it as Integer.
3. You are using "application.run..." to run code in each module, instead, use CALL procedure name.
4. In your sub procedures, you are trying to exit the procedure and return to the main procedure by using the App...run.. language; however, this will only call the main as a subroutine of the calling subroutine and start it from the beginning of the code. Since main is calling each of the subs, you have an untended infinite loop that crashes Excel. If you had CALLed the sub from the main, the End Sub would exit the sub and return to the main at the next line after the CALL line:

Public intrade as Integer
sub main()
    ....
    do some stuff
    ....
    call function_one
    return here from function one and do more stuff
    call function_two
    return here from function two, etc
end sub

sub function_one()
    do something
end sub
sub function_two()
...
end sub

Declare & Type all variables
Use Call vs. app/run