Raphael,

For the one given a specific length have you tried making sure your parameters are at least that big?

ala:
FLen = replicate(chr(0), 255)

Also are you sure it's valid to pass an empty string for the arguments into the function? That maybe causing it to crash as well.

Also sometimes the docs are wrong.. they may say ByVal but really need to be ByRef.

>Here is allof what I could find (i am not a vb person)
>

Public Declare Function BUICScan& Lib "BUICAP32.DLL" (ByVal iJob&, ByVal lpFront$, ByVal FLen$, ByVal lpBack$, ByVal BLen$, ByVal LpCode$, ByVal LpLen$)

>

>'// Declares for BuicScan
>    Dim FLen As String * 255
>    Dim BLen As String * 255
>    Dim CodeLen As String * 255
>    Dim mstrMICR As String * 255
>    Dim mstrFront As String
>    Dim mstrBack As String
>

>

mlngReturn = BUICScan(mlngSides, mstrFront, FLen, mstrBack, BLen, mstrMICR, CodeLen)
>