Code Page are character encoding in Operating System. Characters are identified by codes. Operating System understands characters in code (e.g. ASCII). For example, if I write 'BHASKAR' as string or 66 72 65 83 75 65 82 (which is ASCII decimal by the way), both of them would be same for OS.
These character encodings are defined in Code Pages of Operating System. Different OS has different Code Pages. Code Page 1252 and Code Page 1251 mentioned in SP3D Installation Guide are having different character codes. This may give up a funny result if the platforms for SP3D are shared.
Anyhow, Intergraph doesn't restrict OS usage. In such case, for any project having multi lingual possibility, just check code page of OS. If they match, go for it.
By the way, enjoy Football World Cup.
Till next post, Happy Smartplanting....