"Nowhere to worm!" error on maps with plenty of play space
From Worms Knowledge Base
On the Amiga version of Worms and WormsDC, the terrain generator must render a level in full before it decides whether or not there is sufficient terrain space for terrain objects, landmines, and the worms themselves. If it determines that there is not enough space for these things then it will reject the terrain and generate a new one.
When playing WormsDC on an emulated Amiga this error message can and often does appear on maps with plenty of available space to play. If this occurs with a custom map or saved graffiti map the best option is to re-load the map until the message does not display.
This bug seemed to have been fixed as of WinUAE version 2.4.1, but has returned as of 4.0.0. It's possible the bug is linked to the number of DIY terrains and/or Mountain sets present in the TWDIY and TWMOUNTAIN folders.