1) Use the latest version of mkgmap because that will less likely produce this error message 2) If you use --precomp-sea with mkgmap and you use --no-trim with splitter, try to add --precomp-sea to splitter as well. Although this will produce a few more tiles, it should not add many more problem ways. The positive effect is that you may set max-nodes to a much higher value.
What is a mch higher value? I've tried it now max-nodes=2500000 but it still stopped after this message JVM Memory Info: Current 1197MB (333MB used, 864MB free) Max 1353MB Calculating tiles for problem relations... Heap def new generation total 380480K, used 79242K [0x042b0000, 0x1df80000, 0x21550000) eden space 338240K, 22% used [0x042b0000, 0x08e0b3b0, 0x18d00000) from space 42240K, 4% used [0x18d00000, 0x18f07750, 0x1b640000) to space 42240K, 0% used [0x1b640000, 0x1b640000, 0x1df80000) tenured generation total 845424K, used 275431K [0x21550000, 0x54eec000, 0x5bab0000) the space 845424K, 32% used [0x21550000, 0x32249f88, 0x3224a000, 0x54eec000) compacting perm gen total 12288K, used 5289K [0x5bab0000, 0x5c6b0000, 0x5fab0000) the space 12288K, 43% used [0x5bab0000, 0x5bfda6c0, 0x5bfda800, 0x5c6b0000) No shared spaces configured.
3) If your PC has 2 GB memory, but Windows allows only -Xmx1400m for the JVM, it is probably because the graphic card shares memory. I assume that you'll be able to free memory by changing to fewer colours or smaller resoltion.
My PC has 4Gb (but since it's 32 bits it cant use all 4gb). Changing the graphics didnt help to make more memory free. I guess I should make the area even smaller and run the splitter 4x instead of 2x. Northern France incl Paris+Benelux+Germany is probably too big for this computer.