A1. If you see errors that contains "
'CBTTaskMaintainSpeed' already defined
Error [content0]game\behavior_tree\tasks\monsters\bttaskmaintainspeed.ws(10): Class 'CBTTaskMaintainSpeed' already defined.
Error [content0]game\behavior_tree\tasks\monsters\bttaskmaintainspeed.ws(74): Class 'CBTTaskMaintainSpeedDef' already defined.
Error [content0]game\behavior_tree\tasks\reactions\bttaskisman.ws(4): Class 'CBTCondIsMan' already defined.
Error [content0]game\behavior_tree\tasks\reactions\bttaskisman.ws(15): Class 'CBTCondIsManDef' already defined.
1. Check this solution
http://www.nexusmods.com/witcher3/mods/1541/? (the first one described there: with hacks folder)
2. For game version 1.21 I've uploaded my sources to the misc section of this mod download file "Witcher 3 patch 1.21 script sources for players having problems with compiling any mods" unzip this file into your "<Path To The Witcher 3>\content\content0\" folder and it should fix the general error. Make backup of your scripts folder inside content0 folder before replacing it.
A1.1. If you see errors that contains "
LogWithName", for example this errors:
Error [content0]game\player\playerwitcher.ws(14: Function 'LogWithName' does not take 1 param(s)
Error [content0]game\gameplay\focus\focus.ws(199): Function 'LogWithName' does not take 1 param(s)
Error [content0]game\gameplay\focus\focus.ws(253): Function 'LogWithName' does not take 1 param(s)
Error [content0]game\gui\menus\gwintgamemenu.ws(104): Function 'LogWithName' does not take 1 param(s)
Error [content0]game\player\states\playerdialogstate.ws(4: Function 'LogWithName' does not take 1 param(s)
Error [content0]game\player\states\aimthrow.ws(42): Function 'LogWithName' does not take 1 param(s)
Error [content0]game\player\states\combat.ws(124): Function 'LogWithName' does not take 1 param(s)
Error [content0]game\player\states\exploration.ws(55): Function 'LogWithName' does not take 1 param(s)
Error [content0]game\player\states\swimming.ws(252): Function 'LogWithName' does not take 1 param(s)
Error [content0]game\player\states\vehicles\horseriding.ws(49): Function 'LogWithName' does not take 1 param(s)
Error [content0]game\player\states\vehicles\sailing.ws(56): Function 'LogWithName' does not take 1 param(s)
Warning [content0]engine\telemetrykeyword.ws(9): Native function 'Log' was not exported from class 'CR4TelemetryScriptProxy' in C++ code.
Check this solution
http://www.nexusmods.com/witcher3/mods/1541/? (the second one described there: with CR4TelemetryScriptProxy)
A2. If you see some other errors in most cases this means you have mod conflict with some other installed mod, see below.