You probably don't want to contact the DBI developers. You probably want to contact the developers of the DBD module that you are using.

Of course, it's always possible that if you read the documentation for your DBD module then you'd find out that they already know about this alleged limitation.

Update: As others have pointed out, the documentation for DBD::Sybase (a likely candidate for the DBD that you are using) says this:

In particular ?-style placeholders are not supported

Yet another example of Win's inability to read documentation.