Hi Christopher,
The include files can be either in the same directory as the main source file (the one you're compiling "from") or in the root PBP folder. If you want to have them in any other place you need to specify the full path in your INCLUDE statement, like INCLUDE "D:\MyIncludes\ThisOrThatFile.pbp"

The manual says that USBSERVICE needs to be called at least every 10ms. SEROUT2 CAN take a conciderable amount of time depending on the baudrate and actual amount of data. Lets say you're sending 5 bytes at 2400 baud, each byte is 10bits including a start- and a stopbit so thats 50/2400=21ms. And that's for the actual bitbanging of the pin.

/Henrik.