QT apps crashing on Snow Leopard 10.6.5

Suddenly all QT apps, both included in the QT framework, and any apps compiled using QT have started crashing on startup. A typical crash report looks like this:
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000000
Crashed Thread: 0 Dispatch queue: com.apple.main-thread

Thread 0 Crashed: Dispatch queue: com.apple.main-thread
0 ??? 000000000000000000 0 + 0
1 libQtCore.4.dylib 0x000000010127317b QIconvCodec::convertToUnicode(char const*, int, QTextCodec::ConverterState*) const + 1163
2 libQtCore.4.dylib 0x000000010114d60e QString::fromLocal8Bit(char const*, int) + 94
3 libQtCore.4.dylib 0x000000010111ed1f QLibraryInfo::location(QLibraryInfo::LibraryLocati on) + 5167
4 libQtCore.4.dylib 0x000000010116bf84 QCoreApplication::libraryPaths() + 228
5 libQtCore.4.dylib 0x000000010124812c QCoreApplication::init() + 188
6 libQtCore.4.dylib 0x0000000101248251 QCoreApplication::QCoreApplication(QCoreApplicatio nPrivate&) + 49
7 libQtGui.4.dylib 0x000000010058d303 QApplication::QApplication(int&, char**, int) + 83
8 com.yourcompany.tea 0x0000000100051136 main + 118
9 com.yourcompany.tea 0x0000000100002b78 start + 52

Thread 1: Dispatch queue: com.apple.libdispatch-manager
0 libSystem.B.dylib 0x00007fff873d516a kevent + 10
1 libSystem.B.dylib 0x00007fff873d703d _dispatch_mgr_invoke + 154
2 libSystem.B.dylib 0x00007fff873d6d14 _dispatch_queue_invoke + 185
3 libSystem.B.dylib 0x00007fff873d683e _dispatch_worker_thread2 + 252
4 libSystem.B.dylib 0x00007fff873d6168 _pthread_wqthread + 353
5 libSystem.B.dylib 0x00007fff873d6005 start_wqthread + 13

Thread 2:
0 libSystem.B.dylib 0x00007fff873d5f8a __workq_kernreturn + 10
1 libSystem.B.dylib 0x00007fff873d639c _pthread_wqthread + 917
2 libSystem.B.dylib 0x00007fff873d6005 start_wqthread + 13

Thread 0 crashed with X86 Thread State (64-bit):
rax: 0x000000010293b4d0 rbx: 0x0000000000000000 rcx: 0x000000010293b4d0 rdx: 0x00000000ffffffff
rdi: 0x00000001012a5314 rsi: 0x00000001012a9150 rbp: 0x00007fff5fbfee30 rsp: 0x00007fff5fbfedb8
r8: 0x00000001013a9448 r9: 0x00000001029fc0a4 r10: 0x000000000000000e r11: 0x000000010293b4d0
r12: 0x0000000000000000 r13: 0x00000001012a5314 r14: 0x000000010293b4d0 r15: 0x0000000000000000
rip: 0x0000000000000000 rfl: 0x0000000000010206 cr2: 0x0000000000000000

Binary Images:
0x100000000 - 0x100108fef +com.yourcompany.tea ??? (???) <152D1DBC-9055-820E-2626-DBF83A5CD0D4> /Users/dwwatson/Desktop/tea.app/Contents/MacOS/tea
0x10013e000 - 0x100392ff7 +libQtScript.4.dylib 4.7.1 (compatibility 4.7.0) <6BA38B59-3776-AC13-BC21-

and continues on. Anybody have this problem and maybe know the cause?