According to IBM's documentation:
"If a load rule specifies a file or directory name that includes one or more <SPACE> characters, you must enclose the entire path name in either single-quotes (') or double quotes (")."
http://publib.boulder.ibm.com/infocenter/cchelp/v7r0m0/index.jsp?topic=/com.ibm.rational.clearcase.cc_ref.doc/topics/config_spec.htm

In the example below double quotes are used. Changing to single quotes does not help.

Quickbuild fails with the following error message:
11:40:46,853 [master>win_cc_checkout@emeastomunin:8810] INFO - Executing post-execute action...
11:40:46,853 [master>win_cc_checkout@emeastomunin:8810] ERROR - Step 'master>win_cc_checkout' is failed.
    com.pmease.quickbuild.QuickbuildException: Failed to run command: "C:\Program Files (x86)\IBM\RationalSDLC\ClearCase\bin\cleartool.exe" lshistory -nco -branch main -r -since 28-January-2012.16:07:27 -fmt "qb_cc_lr:%o |##|%m |##|%Nd |##|%En |##|%Vn |##|%u |##|%[activity]p |##| %c" base/jpmorgan base/prod_versions.txt ""/base/FAME/FAME SDK/UnitTest"" base/buildutil
    Command return code: 0
    Command error output: cleartool: Error: Unable to access "/base/FAME/FAME SDK/UnitTest": ClearCase object not found.
        at com.pmease.quickbuild.execution.Commandline$ExecuteResult.buildException(Commandline.java:372)
        at com.pmease.quickbuild.plugin.scm.clearcase.ClearCaseRepository.getChangesBetween(ClearCaseRepository.java:479)
        at com.pmease.quickbuild.plugin.scm.clearcase.ClearCaseRepository$$EnhancerByCGLIB$$3cf75627.CGLIB$getChangesBetween$12(<generated>)
...

Removing the quotes results in the load rule being ignored:
11:41:56,383 [master>win_cc_checkout@emeastomunin:8810] ERROR - cleartool: Warning: 1 objects were eliminated from the new config spec's load rules:
11:41:56,742 [master>win_cc_checkout@emeastomunin:8810] ERROR - Continue, and unload these objects? [no] cleartool: Error: Unable to lookup "FAME" in "\base\FAME@@\main\21": No such file or directory.
11:41:56,742 [master>win_cc_checkout@emeastomunin:8810] ERROR - cleartool: Error: Unable to access "\base\FAME\FAME": No such file or directory.
11:41:56,742 [master>win_cc_checkout@emeastomunin:8810] ERROR - cleartool: Error: Pathname "SDK\UnitTest" is not a full VOB pathname: it does not begin with a "\".
11:41:56,742 [master>win_cc_checkout@emeastomunin:8810] ERROR - cleartool: Error: 2 config spec load rule problems encountered.
...