runtime error for all programs

i recently installed the jdk 1.5.0 in windows xp sp2. i have no problems in compiling a program, but whenever i run it, i get a error : "Exception in thread main : java.Lang.NoClassDefFoundError ". this error occurs for all the programs i try to run

this happens even though the class file is located in the bin directory. also i have tried reinstalling both the jre and jdk, but still no effect. what gets me confused is that the same code runs just fine on linux .

can some one help me out?

[512 byte] By [krapaa] at [2007-10-2 9:50:23]